Well this is a tough question.
My gaming tastes have evolved but haven't changed fundamentally.
Some people say they grew out of platforming or Turn Based RPG's etc...etc... that over time as they grew older they stopped enjoying the genre's they grew up with.
Personally I still love every genre I have ever loved whether it be my all time favorite Platformers to turn based RPG's or Real Time or Turn based strategy games.
What has changed this generation? Well I would say FPS and tactical military games never were my thing. Doom, Duke, Unreal Tournament none of them really appealed to me. But Halo began to appeal to me last generation then during this generation I began playing all kinds of shooters and a genre that never really interested me quickly became one of my favorites.
Another thing that has changed is graphics. GameCube and all generations prior I could care less about graphics. A good game was a good game it could be an Atari 2600 game and still be equally as enjoyable as the latest Call of Duty. However this generation has changed that, I still enjoy all the classics but it used to be if I were offered say Super Mario Bros (NES) or God Of War III I would choose SMB because it was a better game. Today however I still love SMB but the visuals aren't good enough to keep me entertained as long as an inferior but prettier looking game.
In the end today I like shooters and pretty games where as in the past neither really mattered to me.
Some people say I grew out of RPG's but that is not true. I have always been a turn based RPG guy and in the last generation or so developers have moved away from turn based RPG and more and more into real time RPG,RPG's like say Mass Effect seem to much like a shooter then an RPG and other more like hack and slash button mashers. I enjoy the old school RPG's like Pokemon, EvolutionWorld , EarthBound!