I've never been much of a fan of Halo, the level design is crap, the gameplay is too slow, and the multiplayer was a joke.
If Halo had been a PC game and not a Console game at release, it would have been passed over as being "just another FPS", which is from my humble knowledge how it was recieved by the PC gaming public, alot of console gamers with PC's did buy it tho'.
It did give console gamers the first chance to experience a FPS that was playable and worthwhile.