I've only played Hitman:Contracts (3 I think?)on the PS2 and Blood Money on the PC. I had loads of fun on Contracts. One of the few games(especially of that kinda genre) that I went back to a lot.
I only got Blood Money day before yesterday, have done the first bunch of missions (on the 5th) and they've been fun so far. At the moment though, it's a bit frustrating that you can buy all of these upgrades for your weapons, but you rarely need a gun (last mission, didn't even bother taking any guns in, didn't fire a thing)
I'll definately be playing back through them though, even if just to use machine guns a lot. And the ol' first person. heh. It's also satisfying once you know a mission. Man you can just walk right through it 😀