Okay, I paid a ton of bills yesterday (ouch!). Well, while at Wal-Mart I saw Halo for $20 and figured "why not."
Installation was quick and easy (didn't install the Gamespy multiplayer thing), and it runs very nicely on my system (1280x1024, 60fps according to FRAPS). Yes, it looks old, and the textures are on the rough side, but hey...
I actually never owned Halo when I had an Xbox, preferring to do on-couch multiplayer with my buddy Lee on Co-op, so I'm enjoying it. Just playing it on the normal difficulty, and I think I've seen some additional bits not in the Xbox version (mostly in the intro cinematics). Its fun, the difficulty isn't a cakewalk (I can't be stupid about things), but isn't the "I HATE YOU" level of difficulty; as is I feel superior to the marines and Covenant, but not like "god-on-the-battlefield" superior. The keyboard/mouse is making it a lot easier for me too as my aim on the pad was never terribly great; pads required a bit more setup and intentional aiming, whereas the KB combo is a lot more fluid for me.
Its a little odd playing a first-person game now since I've been playing almost entirely 3rd person games (MMO's and the like). I think I'll probably have an easier time with Gears when it comes out.
Anyhow, its fun, even if its old fun.