Just switched from AT&T where I had a terrible old grandfathered plan with 2GB data and $10/GB overage. I regularly went over 2GB and for most of the past year, my phone bill was $110.
I took T-Mobile's 3GB plan for $60:month, with no overages. They throttle down to 3G speeds if you go over. Plus, with the iPhone 5s, there's wifi calling in my house, which gets so-so signal.
The downside is that AT&T has signal in the subway, but T-mobile doesn't. Oh well. I'll take the cost savings.
My new Chromebook w/ 3G wireless (via Verizon, 100 MB/month). Currently $310 at NewEgg, $230 for the wifi-only version. There are sub-$200 models from other manufacturers.
It’s great. Netflix and Hulu work OK - a little stuttering on Netflix occassionally. All the Google Apps work fine: Gmail, Calendar, Documents, etc. There are also text editor apps for light coding. Worst comes to worst, you can edit in GitHub itself. There’s a not-so-great SSH client. A last-resort BitTorrent client, too.
There is Flash built into the Chrome browser, so the usual video sites (YouTube, Vimeo, DailyMotion) work even without using HTML5 video.
Photo editing is a weakness. There are no apps which directly support RAW files: you have to use PicasaWeb, which is now integrated with Google+.
Flickr used to support RAW files of various formats, but does not seem to, anymore. Attempts to upload a Nikon NEF file failed: the fancy uploader just refused it, and the basic uploader took it but only grabbed the JPG thumbnail.
Picasa does accept NEF, and converts it to JPG. It has basic online image editing, like Flickr does. This is how I converted the NEF to JPG to post the image above. Conveniently, this Chromebook has a built in SD card slot, so I can just pop the card in from my camera.