Let's see.
1. Eternal Darkness: Sanity's Requiem - Survival Horror
As a fan of Lovecraft's work, I really liked this game's take on enormous entities that control the very fabric of the universe, and how someone would react to discovering such horrific things. The Sanity meter has been done before, but when it starts running low, some of the best parts of the game shine through. The walls bleed, you'll take hits from monsters that don't exist, and every so often, the game toys with you beyond the forth wall by turning the volume down or pretending to switch your controller port.
The story jumps around with each character discovering the Tome of Eternal Darkness at some point, and from there it shows what happens to them once the book is in their possession. It often leads to a gruesome end, but seeing how each person fits into the overall story is satisfying to discover.
2. Red Faction: Guerrilla - Action/Destruction
The Geo-Mod 2.0 Engine and the gravity mechanics that allow you to topple buildings into expensive debris is one of the most awesome parts of the game, and even now I keep popping it in just to knock down an EDF building that's bugging me. Take a sledgehammer to the building's supports and apply some explosives to finish the rest, then sit back and try not to get squished as you flee from your handiwork.
The story is paper-thin and silly, but if you had access to all the toys and explosives that Alec did, I'm quite sure you would do exactly the same thing.