I would like to buy a smartphone. What is everyone else out there using with GTD? Would you recommend it? What are the advantages and disadvantages?
I use an iPhone. I have had Palms for years before, but when my TX went crazy, I could not see spending the extra money for a Treo over an iPhone. (Yes, that's right, total 2-year cost is less with an iPhone.) I use Remember the Milk and iCal (synced to Google Calendar). It is easy to implement GTD with Remember the Milk. Lots of flexibility, and a good iPhone interface. There are several other web 2.0 apps for gtd on iPhone.
Advantages: as long as the web is up, I have access to my lists just about everywhere, without syncing. The iPhone is great.
Disadvantages: the current lack of cut and paste is stupid, but will probably get fixed. The iPhone is probably not a good option for the crypto-geek uber-businessman ("I wrote a two-hour power point presentation on my phone"), but I have been there, done that, and obsessing over hard-to-use "features" is a waste.