I did enjoy Oblivion, but considering that Fallout 3 and New Vegas were built on the same engine, they feel like basically the same game, but improved over time. I'm supremely excited for Skyrim since the footage and screenshots I've seen so far look like they have a brand new interface for us to work with and improved graphics.
Oooh, I forgot about the Rainbow Six games. Those were great, and I really enjoyed the experience system for Vegas 2, and weapon customization is always a lot of fun.
"I just followed standard video game logic and assumed that the weapon made of gold was the most powerful."