I have this exact same problem. I'm 35 years old, and I've been playing Arcade/Console/PC games since the age of 12.
Over the last 3 weeks I've been scouring the web for reviews, spanning back as far as the mid 80's for gems I may have missed. More and more I'm convinced that I've played every game worth playing.
My favorite games throughout my life so far have been:
(the times when I discovered or played them, not necessarily when published)
Age 12-15: The Bard's Tale, Wasteland, Ultima, Pirates!, Might and Magic 2, Dungeon Master, Gold Box AD&D, Castlevania, The Legend of Zelda, Metroid, Punch Out, Super Metroid
Age 16-24: Dune 2, Warcraft, Warcraft II, Tie Fighter, Mechwarrior Vengeance, Counterstrike, TFC, Diablo, Everquest
Age 24-30: Diablo II, Nethack, Moria, Angband, Zangband, Civilization 3, Baldur's Gate II, Age of Empires II, Shadowrun (Sega Genesis), Half-Life, Daggerfall, Fallout 1&2, Far Cry, X-COM UFO Defense, Battlefield 1942, WoW
Age 30-35: Master of Magic, Master of Orion 1&2, KOTOR, GTA Vice City, Jedi Knight Academy, Pirates 2, System Shock 2, Deus Ex, Thief Gold, Fallout 3, Might and Magic VI&VII, Wizardy 8, Titan Quest, Torchlight, Vampire the Masquerade: Bloodlines, Borderlands, Mount and Blade Warband
There are hundreds of other titles & sequels I've tried which I don't consider worth listing, I'm sure I forgot a few that are.
But I feel like I've seen it all, and that innovation in computer gaming has stopped.
I'd like to believe I'm wrong, and I'm sure there are some great indie titles I would enjoy (Mount and Blade Warband was a wonderful surprise), but it's taking me more time to find a game worth playing than to actually play the game. I don't remember that being a problem before.