As far as I am concerned, the arduino is the best environment for new users. It has everything you need in a $30 dollar package to program the chip and to start designing with it. It has plenty of memory for programs so you don't have to be the most proficient programmer to use one. There is literally tons of information out there for it and the programming environment is quite simple to use. Once you have a working prototype, you can remove your program chip and work it into your own PCB design. These things are so universal there is no wonder why they are one of the most popular uC's on the market.
That said, a firefighting robot sounds like a real challenge. Hope you are up for it!