The Unreal 3 (UE3), Call of Duty 4 (CoD4), and Assassin's Creed (AC, AKA Scimitar) engines have all proved themselves in terms of graphical horsepower and massive sales.  UE3 will likely never be taken down in total sales, but the other two come as close as any engine has and have proven capable to help create mega platinum hits.  Which one of the 3 do you think is the prettiest? 

Below is a short list with some of the biggest announced games for each engine; unreleased titles are italisized. 

UE3: Gears of War; Mass Effect; Too Human; Gears of War 2; Mirror's Edge; numerous others...

CoD4: Call of Duty 4; James Bond: Quantum of Solace; Call of Duty: World at War

Scimitar:  Assassin's Creed; Prince of Persia; Shaun White Snowboarding

(Note: I left off the Far Cry 2 (Dunia) engine, among others, because it has yet to prove itself in terms of console sale's perspective.  Please feel free to discuss other engine's as well though.)

I think I'd have to say Scimitar looks the prettiest to me... the Historical Jerusalem was really breathtaking to behold in AC, and it says something that the game sold so well despite gameplay that was mostly mediocre. 

Prince of Persia is also looking fantastic...

All I can say is I really dislike the Unreal 3 engine. The engine itself is alright, but most games utilizing it look really bad, and tend to look like clones of eachother.

Examples: Frontlines, Army of Two, Jericho, Fracture, Blacksite, Dark Void, Dark Sector, Dead Space... (notice the originality of the names?)

Unreal 3 does a good job and can get it done!!

uncharted engine is also one of the epic ones.. maybe it's only been featured in one game, but all that it does, it does well.. and thats a lot.

CoD4 Engine is nice but not very spectacular. UE3 is beautiful and impressive but I think the first place will get Scimitar.

Umm...Frontlines looks nothing like Blacksite.

Jerecho doesnt use Unreal 3.

Programmers make games using these engines, theya re to blame. In the hands of good devs...unreal 3 is amazing for consoles. Play Unreal Tournament 3 on the 360 and let me know which other game engine runs that smoothly and looks that good.

Well, I'm just saying most of those games look extremely boring, due to the shared development tools and -indeed- the developers. BioShock also uses the U3 engine but looks beatutiful and unique.

I am not a fan of the UE3 engine. Bioshock looked very nice. Gears and UE3 don't appeal to me visually.

Assassin's creed looked cool, but framerate problems let it down a bit.

COD4, just not up there with the greats IMO.

Uncharted looks fantastic. Definitely above UE3 produced quality so far, but lets wait for Gears 2. :)

Metal Gear Solid 4 - amazing (just thought I would drop that one in).