Right now, the RP has a rudamentary X-server but a full ssh server and GCC. It's capable of so much more, just like Linux was 15 years ago. There's hints of what it can do, rendering 1920x1080 video and some VERY capable openGL stuff ( Quake3 at respectable rates) but at present, it's a $35 device hiding a lot of Gee Whiz. Sure any Android device can connect and run some really cool apps but RP can do such more, has the same latent capabilities Linux did, the same capabilities that captured the imaginations of so many, the capabilities that have brought Linux to where it is today.
RP is a year old now but it's in a position where it isn't going to get stale, where a 300MHz P2 and a 3DFx Banshee card would be pretty awesome. Sure it won't run Crysis but it's a wholey remarkable piece of hardware and one that does or should capture the curiosity of every Linux afficianado over the last 15 years and the attention of anyone who has gotten excited about Linux in the last 15 years.
Android is as nearly locked up as IOS but RP is as wide open as . . . GNU linux.