Which do you prefer? I'm going with NFL2K2 for the familiarity. I've been playing the 2Ks on Dreamcast and love them. I love the controls, speed, and everything. Which do you like and why?

I love both. I have Madden 2001 for PS2. I am going with NFL2k2, just for a different football experience considering Madden 2001 is hard to improve upon. You really can't make a good argument that one is better than the other - just a matter of preference. If you're accustomed to the Sega Sports series, then by all means get NFL2K2. You'll go nuts playing Madden only to find you're unable to scramble out of the pocket.

all the players on madden look small and fat

I've played both series and I prefer Madden's more simulation gameplay than the 2k's series arcade gameplay, although both of them are great football games.