I used to replay RPGs (Baldur's Gate 2 and Deus Ex come to mind), but I find that they're definitely not as fun the second time around and I start getting bored. I'm also getting to the point in my life where my gaming time is decreasing more and more (that's aging for you), so I have to pick and choose what I play.
I still enjoy replaying FPS games though. I've replayed Jedi Knight 2 and Half Life 2 the most, but I've replayed No One Lives Forever, Half Life 1, and a few others more than once also. JK2 and HL2 never get old for me - I've replayed each at least 3 times (JK2 probably 5 or 10).
I really love the core gameplay of the Hitman series (where's the next one?), so I never tire of replaying them as well. I like the gameplay improvements of Blood Money, but I love many of the levels from Silent Assassin and Contracts, so I replay them just as much.
Post edited November 07, 2008 by Ecthelion