This is an interesting spread of devices, perhaps a little smaller than expected but it's still early days and Nokia themselves say this list will expand in the future.
Hopefully we will see all future S60 3rd Edition models include Next Gen N-Gage compatibility. If Nokia do that, it could build up a userbase bigger than all current games consoles put together.
The new N81 and N81 8GB models have a gaming mode. The phone is held horizontally with the direction pad on the left, and two hidden buttons light up on the right, turning the whole thing into a simple joypad:
