Controller

There'll be plenty of 3rd party support. The games will be very, very cheap to develop for. As such, many smaller developers will be putting out Revolution games. While we may not get games like Prince of Persia, or something, but Rev owners will play lots of new series and more unique games.

Plus, some games will end up playing better on the Rev too. The controller would be perfect for playing something like Splinter Cell, or RE4 (maybe 5).
 
Several third party developers have already expressed a lot of interest in working on the Revolution.

However, the controller that was demoed is apparently not the sole controller configuration for the system. Supposedly there is a more "traditional" controller that will be available, and it will likely see use on multiplatform games and such.