I voted for other. Jade Empire is my GOTY even through it was not till the 2007 PC release that I actually played. I loved the settings and combat system. The story was not amazing but good enough. It really the combat system, level and monster design that really stood out to me in this game as being great. The only big problem I had with this game is it really short. Even doing every possible optional the game can be completed fairly quickly. Not as big deal for me but other complaint would be choices don't really affect ending other then one. You could play the entire game evil and make the "good choice" on one option and get the good ending and same other way around.
Game I played the most in 2005 was Serious Sam 2 but mostly because I had a friend who lived far away and this was the main game we played together online in 2005.
If I was playing a FPS solo in 2005 then I was probably playing F.E.A.R which is a enjoyable Horror FPS that introduce a slow-motion mechanic in combat that I thought worked well.
Finally Dungeons & Dragons: Dragonshard was an enjoyable RTS from 2005. I not saying it as good as warcraft 3 but I enjoyed the eberron setting and the fact they added hero unit and some form of questing.