In Halo 2 the highest I could get was 35. Anyone you faced after that rank was either modding or standbying... it was ridiculous.
Halo 3 I think cleared up a lot of the problems, but there were still many. Nevertheless, it took me 49 days after Halo 3 came out to get to lvl 50. It was a very glorious Monday when I finally got it. To go from 49 to 50... I had to win 16 games of Team Slayer in a row. We only had a team of 3. We would go into matchmaking, and back out in the pregame if more than 3 opponents joined. This set us up with constant 3v3 matches that we felt comfortable winning.
Now Reach... I don't even know what to say about it. I will be playing my 10th day of Arena season 2 tonight, so ill post back what my division was later on. The first season I got silver.