It depends on the individual and their lifestyle. I agree, though, you'll get a lot for your $400. If you have broadband you can get free demos and simpler games, and depending on your setup at home you can transform the 360 into a major multimedia center. Great if you happen to have family over and wanna share pics or home movies that you can channel from your PC (XP Media Center Edition, though). In between game sessions you can play your iPod on it, chat, check email, instant message, wash dishes, do the laundry, spy on your supermodel neighbour.....
Also, there will be a great number of games coming out in the next 6-12 months, and who knows what other goodies will come from online.
Gawd, I sound like a pimp.