Afaik, GameStop's deal is for first party games only. It could be the same for the other two for all I know, but I'm gonna check them first just in case.
For now, I'm eyeing Wipeout, Lumines, and a third game I haven't decided on yet (Hotshots or VT4).
The only downloadable games I'm looking at so far Super Stardust and Escape Plan.
I placed my amazon order last night, but I'll try lockerz today, and see how it goes.