Sorry for the bump but I can no longer edit my post, I don't think I'll use Speed 900s because I can't find any info on operating and stall torque and I don't want to buy something that expensive not knowing what it'll do. Hmm.

My main dilemma really is that I'm new, but I don't want to design a bot that chundles around the arena and just stops when it hits stuff. But I can't over complicate this thing because I have absolutely no robot building know how.

How do drill motors compare to the motors manufactured for model boats etc? I'm not even sure what motor I want because the only ones I can find don't tell me what there operational torque and stall torque are, and places like technobots I don't even know what I should be looking at.
The tutorials are helpful, but without certain background knowledge on things like motors batteries, what sort of esc I'd need and what sort of speed controller I'd need I'm dead in the water. And it's annoying because I've only just realised. It's probably down to that I'm not looking hard enough but I don't even know where to start since half of this stuff makes no sense to me at all.