Gears of War for the PC is close to being a perfect port.
Take the original game's content out of the picture for a moment. Forget the fun cooperative firefights and the flanking maneuvers. Ignore the visceral melee combat and punched-up violence. Don't pay any attention to the detailed architecture and solid level design.
Here is a textbook example of a smooth transition to the PC.
The game's menu looks nearly identical to the Xbox 360 version. The multiplayer operates in much the same way, with matchmaking supported by Games for Windows Live, supporting the same local and online cooperative options. Even the PC version's achievement points can be carried over to your Xbox 360 score. All of this works wonderfully.
But much like Resident Evil 4, Gears of War was a deliberately paced game, and not one that would immediately take to the PC platform. Though it adds new content in the form of five singleplayer chapters, three multiplayer maps, and some improved visuals, it all really comes down to the controls--and thankfully, developer Epic Games has nailed that aspect in every way.