I guess these games have the best engines.

Aion
MW2
Halo 3: ODST
Resident Evil 5

1 Assassin's Creed II
2 Fable III
3 GT5
4 Forza 3
5 Trine

My top 5 this year SO FAR.

1. Killzone 2
2. Resident Evil 5
3. Batman: Arkham Asylum
4. Muramasa: The Demon Blade
5. Fight Night 4

Here's mine,

#5- MW2
#4- Muramasa: The Demon Blade (Not technically strong, but damn pretty none the less)
#3- Mass Effect 2 (I know it's not 2009 but it's close enough :P)
#2- Uncharted 2
#1- Killzone 2

Great minds think alike

Including unreleased titles:

1) Uncharted 2
2) Gran Turismo 5
3) Killzone 2
4) Forza 3
5) R&C Future: A Crack in Time (not realistic, but I like it artistically).

Only released titles:

1) Killzone 2
2) Resident Evil 5
3) Flower (shame on you all for not naming this!)
4) Batman: Arkham Asylum
5) n/a (can't think of anything else worthy of a mention).

1. Naughty Dog Engine 2.0

1) Killzone 2
2) Uncharted 2
3) Flower
4) Assassin's Creed II
5) inFAMOUS

Hmm, I haven't seen anything spectacular in terms of graphics this entire year (with the exception of Killzone), but so far the list looks like this:

1. Killzone 2
2. RE5
3. Batman: AA
4. Fight Night Round 4
5. Street Fighter 4

For released games:

1. Uncharted 2 (I really think this game one-ups KZ2)
2. Killzone 2
3. GT5
4. R&C
5. AC2

5) inFamous
4) GT5
3) Eyepet
2) Killzone 2
1) Uncharted 2