What materials do you most commonly use on your robots?

[Oblarg]

449 just made the change from predominantly 80-20 frames to 2''x1'' aluminum tube (and good riddance to the 80/20, it's a terrible material that breeds bad habits and should only be used for prototyping, in my experience), assembled with match-drilled gusset plates and 1/4''-20 bolts. Easy to do and very sturdy.

4464 this past year used the standard kitbot c-base frame, with a superstructure of aluminum tube of varying sizes and riveted gusset plates, which worked great.