-League of Legends - About 2,500 matches played across closed and open beta, and release. Used to be pretty goodish, but my skill drops off surprisingly quickly in that game when I don't play constantly. I'm pretty bleh now, and don't play very much. I just hit a point where I stopped "getting it," I couldn't feel my way through situations anymore and started to suck. Still play the occasional game when my old group needs a 5th. But hey, I FINALLY got my master beta tester icon! I thought that would never happen. So, now all the time was worth it xD
-Counter-Strike ~1.4-1.6 - Hundreds of hours. Played a ton of this at home and at a local LAN gaming center. First game where I discovered the rush of competitive multiplayer.
-World of WarCraft: BC, WotLK, Cata - Played this off and on. I'm not sure how much time I've accumulated. I think my main was around 30 days last I checked... ages ago. Had another character that probably got somewhere around that, plus a plethora of alts. Probably around 80 x 24 hours played, I'd guess.
-Team Fortress 2 - Steam says 222 hours, but 80% of my TF2 time took place before hour tracking. I'd surmise 1000+ hours have been spent in TF2. One of the few shooters I got "good" enough at to consider myself decent.
-The Elder Scrolls: Morrowind - I recall reinstalling this game A LOT so I assume I've played this to death. Likely hundreds of hours. This was before my mental integration with the internet, so even after all that time, so much of Morrowind's world and mechanics were a mystery to me, and I loved it. Will probably never experience something like that again (because these days I'd be frustrated by my lack of understanding). Ignorance, in the case of Morrowind, was bliss.
-WarCraft 3 Custom Maps - Seeing what the community could come up with was so much more interesting than the actual game. WC3's endless variety of custom maps entertained me for years. Favorite of all was ENFOS Team Defense, which probably what opened my mind to DotA (where I was immediately crushed, and ran away from it) and then to League.