Being a non-owner of Xbox, I eagerly awaited the Halo experience on PC.  True, when expectations are high, it often results in a let down - as it did with Halo.
SINGLE PLAYER  - 3.5 out of 5
It's not to say that Halo isn't fun.  It is.  However, I was expecting better.  The highly acclaimed "story" is, in my opinion, rather weak.  From what I had read and heard from Xbox owners, I had expected a "Deus Ex" type story experience.  Not even close.  The story is rated a 3.
I had also expected highly developed memorable characters.  Again not true.  To be fair, however, the story and characterization is  "above average" for a FPS.  But it is just not at the level I had expected.  Characterization rates a 3.
Playability is fairly good.  The weapon selections and effects are solid.  Movement and customization was adequate.  The mouse and keyboard playability was typical for a FPS.  There were some glitches, however.  The vehicles handle more poorly  than I had expected.  There are also a few clipping problems and slowdowns, even with a high-end machine.  I rate playability 3.5
Graphics were good.  But, again, not quite at the level I had expected.  Maybe it was unfair to compare the graphics right after playing Unreal II.  The audio was very good.  Graphics and audio rate a 4.
MULTIPLAYER  - 2 out of 5
Multiplayer is a huge disappointment.  I had read many reviews which claimed multiplayer to be far and away the BEST thing about Halo.  For PC, the opposite is true.  First, I would suggest you tweak your settings to achieve the best performance possible.  Slowdown is a killer in Multiplayer FPS.  Even on the lowest settings, tweaked, and a 530 Kbs DLS line, I still have lag problems.  And lag is not good.  Halfway through a tunnel, I suddenly find myself outside.  Opponents suddenly disappear right in front of me.  I walk close to a ledge and then find myself dead from falling off.  I shoot an opponent in the chest with a missile, only to find out he was 20 yards ahead of where I see him on the screen.  Not good.
The most frustrating thing about multiplayer is the lack of any type of system to boot off game ruiners.  EVERY team based game I have played  had "betrayers."  Not only do you have to battle opponents, but also the very immature idiots on your own team that try to kill you.  There appears to be no recourse for such behavior and the develops appear to refuse to do anything about it.  It's a complete joke.
There are also problems with the physics.  Quite often I shoot a missile at a vehicle, which tumbles it into the air, only to have the vehicle suddenly right itself and keep going as if nothing happened.
Needless to say, I am very disappointed in the multiplayer experience.
Overall, I give Halo a rather generous 3 out of 5.
Being a non-owner of Xbox, I eagerly awaited the Halo experience on PC. True, when expectations are high, it often results in a let down - as it did with Halo. SINGLE PLAYER  - 3. 5 out of 5
It's not to say that Halo isn't fun. It is. However, I was expecting better. The highly acclaimed "story" is, in my opinion, rather weak. From what I had read and heard from Xbox owners, I had expected a "Deus Ex" type story experience. Not even close. The story is rated a 3. I had also expected highly developed memorable characters. Again not true. To be fair, however, the story and characterization is  "above average" for a FPS. But it is just not at the level I had expected. Characterization rates a 3. Playability is fairly good. The weapon selections and effects are solid. Movement and customization was adequate. The mouse and keyboard playability was typical for a FPS. There were some glitches, however. The vehicles handle more poorly  than I had expected. There are also a few clipping problems and slowdowns, even with a high-end machine. I rate playability 3. 5
Graphics were good. But, again, not quite at the level I had expected. Maybe it was unfair to compare the graphics right after playing Unreal II. The audio was very good. Graphics and audio rate a 4. MULTIPLAYER  - 2 out of 5
Multiplayer is a huge disappointment. I had read many reviews which claimed multiplayer to be far and away the BEST thing about Halo. For PC, the opposite is true. First, I would suggest you tweak your settings to achieve the best performance possible. Slowdown is a killer in Multiplayer FPS. Even on the lowest settings, tweaked, and a 530 Kbs DLS line, I still have lag problems. And lag is not good. Halfway through a tunnel, I suddenly find myself outside. Opponents suddenly disappear right in front of me. I walk close to a ledge and then find myself dead from falling off. I shoot an opponent in the chest with a missile, only to find out he was 20 yards ahead of where I see him on the screen. Not good. The most frustrating thing about multiplayer is the lack of any type of system to boot off game ruiners. EVERY team based game I have played  had "betrayers. "  Not only do you have to battle opponents, but also the very immature idiots on your own team that try to kill you. There appears to be no recourse for such behavior and the develops appear to refuse to do anything about it. It's a complete joke. There are also problems with the physics. Quite often I shoot a missile at a vehicle, which tumbles it into the air, only to have the vehicle suddenly right itself and keep going as if nothing happened. Needless to say, I am very disappointed in the multiplayer experience. Overall, I give Halo a rather generous 3 out of 5.