Wanting to build a 75 - 100 lb robot..... what type of drive motor do I need?

Question

and also... do I need any dual channel motor speed controllers or anything like that to do this??

Answer 1

Are you on a budget? if yes, then 12v vehicle starter motors might be OK, but a little underpowered for 100lb. better is to go for a 18~24v system, net search for 'EV Warrior motor'.
You will need speed controllers to have any decent control. Vantec or Pololu are good brands to look for. If you are on a budget and can give up some finesse then you can use RC switches (they act as on/off switches in reaction to the radio signal) to drive some high current relays. your robot will go full speed or stop, nothing in between.