[dustinjeremy2k]

I'd like to encourage teams to draw lots of diagrams, mock up rolling chassis, and think about the assumptions you are making before designing a "drive base".

Basics
4WD skid - simple, effective, stable climber. If it's designed to stand a chance in a pushing contest, it won't be very maneuverable.
6WD skid / tank tread - a bit heavier, more moving parts, NOT a very stable climber, much more maneuverable, still good at pushing (Usually the best "compromise" chassis, but not this year).
Omni / Holonomic - very versatile, simple, maneuverable, but you're on roller skates, and can't climb well (or at all).
Crab / Swerve - similar to above but with superior traction, superior handling, more complex, many moving parts, not likely to be a good climber. Does not (usually) rotate the chassis efficiently which could lead to more complex (multi-sided) game mechanisms.

I think the best drive systems will be some sort of hybrid between two of the basics. I would NOT use a tread or a crab to climb... good luck to those who try it! (And do you really need to climb anyway?) If you do, you might want to bring a big tool box to the competitions!

Enjoy!