Which of the "HD Twins" should santa bring me this Christmas?

[makingmusic476]

If you're serious about renting each console, I say try out these games on each platform (sans Halo and Metal Gear, though ODST and MGS4 are excellent games):

360:

Mass Effect
Fable II
Gears of War 2 (if you like it, get the first!)
Forza 3
Lost Odyssey

PS3:

Uncharted 2 (if you like it, get the first!)
LittleBigPlanet (give it another shot - play it with the GF, it's an amazing multiplayer game)
Killzone 2
Valkyria Chronicles
Ratchet & Clank Future: A Crack in Time

And if you can track down the God of War III demo, give it a go.

I'd also recommend Demon's Souls (my GotY), but sadly you Euros seem to have been passed over on that one. =/