There's a new, albeit short, preview of Halo on the PC done by Gamer's Pulse; it's got a quick rundown and some screenshots that suffered the usual fate. Their take is basically that it's worth it for the Internet multiplayer enhancements:

Halo's multiplayer on PC is distinctly more strategic than on Xbox, offering additional maps and weapons, as well as more strict gameplay parameters. When hosting a game, you'll be given a multitude of options regarding game parameters such as armor strength, starting health, the number of vehicles placed on the map, etc. You'll be allowed to hold two weapons and two types of grenades during play, forcing you to strategically decide which weapons will best serve your style of play. The addition of the Banshee, along with other vehicles, throws in another strategic element to gameplay, encouraging cooperative play and creative tactics. The new maps feature several vantage points for sniping, an element found heavily throughout the campaign.

Thanks to Blue's News.