Considering you still show an interest in gaming, I would never say that you've lost your mojo. As new games come out, including repeats of each other, it sort of makes it difficult for the long-term gamers to adapt. I mean, Call of Duty, as great a game as it is, is certainly not a fresh experience unless you just haven't played it in quite some time. Call of Duty and Halo have reshaped FPSs on console so they are nowhere near the same as before... which makes it easier for younger, newer gamers to come into the picture and become good at it. Those same gamers though would most likely get reemed playing us at Counter-Strike though. ;) (For the most part). As far as wanting to go back and play old titles... it's just like when you go to a restaurant and order the same thing. Sure, you want to try something else, but do you want to waste the money on something you might not like? Or just buy what you know you will like?
I stay active as I can with gaming. I love all the old games I've played and enjoy a lot of new games. My suggestion to you would be to ask around, see what your friends like... play some demos, etc. Find a genre you like and check out other games in that genre (Obviously there's no game like Heavy Rain, haha). You said you didn't like AoE 3, so stay away from RTSs. And also stay away from sandbox games like GTA (Mafia, Just Cause, Saints Row, Red Dead Redemption), etc. You should look into some of the newer style FPS hybrid genre games like Bioshock, Fallout, etc. Or even trying some of the newer RPGs like Mass Effect, Oblivion (few years old I know), etc. I would say... never give up on the gaming spirit. The fact that you asked Slashdot about this means you still show interest. Gaming for life!