I'm going to create a small 2-wheel robot, and want to ask for some help about the hardware, mechanic part of it. The robot brains will consist of a beagleboard, not arduino, but I think it doesn't matter much here. I myself am more a software developer and mathematician, so the programming part hopefully will be ok 
At first I'm not sure which motors to buy. The robot weight will be about 500g, so I think these 6V motors (with 7 cm wheels) are enough. Am I right here?
Another point is mechanically connecting all the things - motors, sensors, controllers, beagleboard, maybe a camera in the future... For simplicity I looked at plastic plates like this one, but again not sure if it is possible to place and somehow secure all the components there.
Any other advice are welcome too
You could interface to motors with an adapter having Lego Mindstorm NXT jacks...
http://elinux.org/Beagleboard:BeagleBone_Motor_w/_NXT_Connectors
The NXT motors are pretty good and easy to work with.
charliesixpack:
You could interface to motors with an adapter having Lego Mindstorm NXT jacks...
Beagleboard:BeagleBone Motor w/ NXT Connectors - eLinux.orgThe NXT motors are pretty good and easy to work with.
They seem way too slow - about 100 rpm, I'd want something faster