This will be my third year for NaNo, I did the past two years on a netbook (and hit my 50K both years).
I gave my brother my netbook ever since I bought my iPad, and this year it'll be an iPad NaNo for me as well. I have a MacBook Pro, but I focus on writing much more when I'm on a device that's just got a text editor up. I have iOS 4.2, so I technically could hop around and surf the web with multitasking, but I have a tendency to just focus on the writing when I'm on the iPad. On the MacBook Pro it's all too easy to ADD out on some RSS feeds or the latest forum posts here when I should be writing.
For hitting my word count daily (I tend to target 1800-2000 words a day to account for "slack days"), I'll probably use my Apple Bluetooth keyboard. It's small enough to go in my daily bag and tote around with me to work. If I'm short a few hundred words for the day, I have no problem working with the onscreen keyboard in bed. The Apple keyboard helps with speed though, and less going back and correcting.
Make sure you use an editor that lets you backup to Dropbox or something, so you have a safe backup. I use "Elements for Dropbox" which is a plain editor that has word count, and saves to Dropbox. I'm also using "Index Card" for plotting -- it will be integrating with Scrivener for Mac soon, so that'll be a nice addition when it happens.
It's a challenge, but completely do-able, even with a full work schedule and hectic after-work calendar. I use lunch hour to crank out words, and then finish up that evening after dinner when the zombie box is on.
Good luck on NaNo!
http://www.nanowrimo.org/eng/user/410845