Why not elaborate a bit on the choices; give a few reasons on why your top 5 consist of certain titles, and what you look for in a game? Better than just a repeated topic.
1. Mass Effect
2. Mass Effect 2
3. KotOR
4. Jedi Knight: Jedi Academy
5. Half Life 2 (Ep2 specifically)
Honestly I feel mass effect has spoiled me. I struggle to play other things sometimes, because of lacking in cinematic presentation, depth, memorable characters, story, dialogue, and a nice bit of action to go with it.
Sadly I haven't felt tempted by dragon age or the witcher because of the gory dark fantasy setting - I just don't get on with it.
Skyrim - well it is very good, but after 80 odd hours the shallowness is noticable, and the motivation for playing pretty much boils down to developing the player character - but because of losing interest/care for the npc characters and game world, developing the player character is a waste of my time; I'd rather do something in "real life". In essence too much freedom => shallower game (characters/story) => I lose motivation for playing. This applies to most sandbox games (borderlands, fallout and so on).
I don't care much for generic shooters (COD/BF), unless playing with friends and that would be on console, purely for socialising.
I don't place such rigid constraints on short games (portal, mirror's edge etc) because it's only half a dozen hours of my time. I wouldn't have them in my top 5 because they're novelties to showcase different concepts/features.
Older games (like Deus Ex), despite them being good at the time, are now very much a struggle to get in to because of the visual and aural quality. Sad but true. Unlike movies that endure, my top 5 games will continue to change as technology evolves.