Just because I am a Halo fanboy, I have to point out some errors in your post.
Halo CE: released in 2001.
CoD Modern Warfare (assuming you mean the first MW, call of duty 4): released 2007.
A 6 year gap does not constitute around the same time, especially in the video game industry.
Halo CE is often credited as being one of the first of the new brand of shooters that came out in the early and mid 2000s.
Sorry, just had to say it. No harm no foul. Your "most overrated piece of junk I have ever played" stings, but as it is your opinion I shall leave it go.
As to OP: I wouldn't worry too much Taak Farst, I went through a stage like that myself a few years ago. It forced me to branch out in to different games and genres, and it broadened my horizons as a gamer. I'm not sure how extensive your game library is, but I would recommend skimming sites like gameinformer or gamestop, and just try to find something a game, series, or even developer that you have never had experience with before (that has received mid to high ratings). You might be surprised at what you find and latch onto a new game with the same vigor you had before.
To one of your points: yes there is going to be an MMO of Elder Scrolls, but it is being developed by a company other than Bethesda, so I wouldn't worry about that either. The keepers of the Scrolls so to speak will still likely make more single player ES games.