First actual computer game I owned:
Mechwarrior 4, it was the only game i played when i was 10 years old.
Jedi Knight: Jedi Outcast and Jedi Academy, most of my middle school years were devoted to this game
Morrowind, same timeframe as JK2 really, and even then I only managed to level up to 30 something with 3 characters
Oblivion had a little playtime, but it really wasn't as indepth, i mostly ended up cheating up to high level characters to mess around, since it really didn't have the same vibe as morrowind (what could have fixed that would have been no fast travel, and a silt-strider/boat system like morrowind had)
My current timesink is TF2, which isn't a bad thing at all, especially with the new updates, etc.