My day to day computing and communication needs are now met entirely by mobile devices, which has only happened since 3G data has become cheap, and I have ready access to wifi at work and elsewhere.
There's very poor mobile coverage where I live, so I use a femtocell (Vodafone suresignal) which connects to my broadband. This means I actually get a useable signal for sending and receiving texts, and I use my bundled mobile minutes to save money and call mobile phones, when they would otherwise go to waste. One day I hope that mobile coverage with fast data (LTE) will reach my home and by cheap and good enough so I could consider not having broadband at all, but at the moment my broadband costs about three times my monthly Vodafone bill, but I get 80 times the data allowance, so it's ~25x cheaper!
The only fixed computer in my house is a low-powered (electrically and computationally) custom-built file server, plugged into a big UPS, and in the event of a power cut it stays up for over an hour! It has static public IP addresses (IPv4 and IPv6) and I can access it from anywhere in the world over a VPN. I have very good internet service, FTTC, giving me ~40 Mb/s download, and 5Mb/s upload, so I can actually stream music and video from it if I want to; and it only costs about £25/month! I have a Slingbox satellite receiver from Echostar so I can remotely manage it and watch my home TV service in pretty decent quality.
I used to use a desktop computer for serious work, but it's old (over eight years) and very slow and hasn't been turned on in months and months, and now only gets used when I need to use it to test hardware which I can't plug into my laptop computer!
In the past I used a relatively low-powered laptop computer for web and email etc, and did the serious work on the desktop (such as crunching DVDs for mobile viewing), often remote controlling the desktop with ssh, VNC or remote desktop. I could thus sit anywhere in the house and do basically anything I needed.
I recently realised that both my laptop and desktop were underpowered, and decided not to bother to replace the desktop since it's possible
to buy very high specification laptops at reasonable prices, and by concentrating my budget on a laptop was able to get something quite decent. My wife wanted an upgrade so got my old one to replace her netbook.
Because my laptop is my only decent bit of computer equipment I have put in a lot of effort tuning it for my needs, to make it boot fast and have all the utilities and tools I use. A key point was to ensure all the drivers for 3G dongles were perfect, and mobile phone tethering worked faultlessly. However, as well as making it easy to use, I had to ensure it was secure since it is my primary device it contains far more of my personal data than I've ever previously carried, so set admin passwords on boot, on the hard drive, and used encrypted disks for secure data storage.
The hard drive is big enough to store music, videos, my 40+ GB of photos etc, so I don't need to decide what to take and what to leave if I go away on holiday as it usually goes with me.
The laptup dual-boot linux and windows, I rarely fire up windows on the "bare metal" but it is the only way to run some games. I also use a windows virtual machine within linux, used quite rarely, as there are a few things for which there's no substitute.
When I'm actually mobile, I rely on a mobile phone, I don't have a tablet, as I wouldn't have cause to use it that much: I drive to work rather than commute by bus or train, and when I am at work I use my work laptop and secondary screen, so there's no place where a tablet gains me anything over a proper computer.
My phone is an android phone, an HTC Doubleshot (like the Desire Z but newer/better). I chose it because the keyboard makes it much more than a media consumption device, it is actually possible to type a decent length email on it, and it means you don't lose half the screen to a virtual keyboard when composing mail, typing notes into Springpad, writing texts etc.
I use a laptop computer at work too, because I am required to be part of an out of hours support team. In fact in my last four jobs the only choice of computer has been a laptop. My employer issued me with a USB 3G dongle to go with the laptop, and a blackberry. I don't like the blackberry much, it's OK for scanning recent emails but sucks compared to gmail on my android phone, and since my android phone has a keyboard there's no advantage in using the BB at all, although it does have reasonable battery life!
My work laptop is also dual-boot linux and windows, spends most of its time running linux, and I use virtual machines a lot for testing. I find that linux suspends and resumes faultlessly and I've had virtually no problems with getting linux drivers, which is not the case for Windows! The only essential accessory for me was a second network card, because of the work I do, and that's one of the few times a desktop computer would beats a laptop as it's trivial and cheap to have lots of network cards in it.
I also have a tiny Fujitsu ultra-portable netbook (U820) with 6" screen which also dual-boots linux and windows. It doesn't get as much use as it deserves, to be honest, but it is invaluable at times as I can literally carry it everywhere and it needs no accessories other than a small cat5 dongle to be a complete laptop replacement.
I am pretty tied in to Google, using a google hosted domain account. I utterly rely on them, and use most of the services (gmail, calendar, docs, maps etc), although I use mostly use Yahoo's flickr instead of the much poorer Google picasa picture service, I use picasa for sharing private photos within the family.
Since I use gmail I don't need anything other than a web browser and internet service, but since I don't trust other people's computers I would only borrow a computer for gmail if I absolutely had to.
I use my mobile devices for..
* browsing the web
* having access to my contacts list at all time, sync'd across phone and desktop
* having my calender with me at all times, sync'd across phone and desktop
* reading the news with Google Reader - which synchronises the feeds I choose as well as read/unread articles, so I can switch between devices any time and carry one where I left off
* listening to podcasts with Google Listen on my phone, mainly in the car with a generic car holder
* playing games, "casual" ones like Angry Birds.
* skype and internet (SIP) phone service, saves me a lot of money when travelling
* maps and navigation
* taking casual photos and videos on phone and transferring them wirelessly to online services like picasa, flickr and youtube
* listening to music - a 32GB memory card in phone, and lots of free disk space on laptop, means I can carry a lot of music with me
In general, unless I have a very good reason, I keep my phone with me everywhere. I don't need to, but it was easier to adopt that habit than to sometimes leave it behind thinking I might not need it and then regret not having it!
Although my HTC phone's camera is not bad, I generally reach for my Canon Powershot which I nearly always carry with me. The downside of the Canon is that I can't edit or upload photos without using a computer, so sometimes I switch between them during a photo session so that I can have the instant upload gratification and follow it up with proper quality pictures!
Whether I go away for a weekend or a week, I take a laptop with me and my phone. I frequently go to the USA, and free wifi is everywhere - hotels, coffee shops, shopping centres, even book shops! Since roaming mobile data is expensive I disable it completely on my phone, and I don't answer the phone, instead, I note the number and call back using an internet phone service which is dirt cheap and uses the free wifi for a connection.
Ten years ago...
* I might have anticipated that some or even half of my computing activity would be on entirely mobile devices, but wouldn't have expected that I'd not bother with a fixed computer at all.
* I did expect 3G coverage to have become much better, but on the other hand I didn't expect it to become quite affordable despite being 25x more expensive than broadband.
* I wouldn't have anticipated that my smartphone would be more powerful than my desktop computer of that time
And that's my mobile life in, well, quite a large nutshell!