I got Halo 3 this morning and have gotten to play 2 chapters..I think. There really aren't chapters like there was in the first one. I've gotten past 2 major load screens..before that meant chapters..
This graphics are good. Not wow factor like the first time I saw Gears of War, but definitely a step above the previous versions. I'm enjoying this one the most. I haven't gotten completely used to the new controls (b is now deploy shield and right button is reload. I can't tell you how many times I've wasted a shield trying to reload..) but overall I think the boys at bungie got this one right.
I'm really looking forward to playing with the level editor..