Help picking a microcontroller

I am on an engineering team making a robot for a project. I have dealt with the Board of Education last year in one of my classes but for this project I wanted to try and get a better controller that can handle more that the BOE did. A rough idea of what needs to be controlled is 2 motors for the wheels, 2-3 other motors (dont have to be as big as the wheel motors), 2-4 servos, distance sensor, and probably 2 light sensors. We haven't come up with which motors, servos, or sensors yet, still in the planning stage. I just wanted to see which micro controller I should look at getting and if I will need a motor shield or not.

you don't need a motor shield for that, but it sure would make your life easier. Any of the Arduino line should be able to handle those requirements, assuming a proper (separate) power supply for the servos and motors. I think the Uno is a good choice, with a motor shield. The microcontroller choice is much easier than building a proper power circuit to handle all those motors and servos. Not that it will be crazy difficult though, especially if you use a motor shield.

Good luck!

Thanks for the quick reply. I just wanted to make sure that we had enough ports to handle the amount of motors, servos, and sensors so wasn't sure if the uno would be enough or would have to go to the mega.

Does anyone mind either sending me a link or explain quickly how we could go about ensuring that we use a separate power supply for the motors/servos than the board? Is it as easy as just using the motor circuit and connecting the power supply to that or will there be any feedback into the board? I just don't want to fry or mess up the board. As you can probably tell I am not really good at electronics, I get basic points and such from the class I took but proper terms and circuit setups have slipped lol. Im good at following directions and hooking up the circuit.

Thanks in advance.

Make a list of how many IO pins are needed. If the motors need to go both directions, they will need 2 IO lines each to control an H bridge.
I count about 15 IO needed then.
Motor/servo supply - yes, just connect their Positive/Gnd supply lines up. Connect the Gnd to the arduino Gnd as well.
If you are using a bunch of stacked up shields, the Gnd will be connected via the headers.

CrossRoads:
Make a list of how many IO pins are needed. If the motors need to go both directions, they will need 2 IO lines each to control an H bridge.
I count about 15 IO needed then.
Motor/servo supply - yes, just connect their Positive/Gnd supply lines up. Connect the Gnd to the arduino Gnd as well.
If you are using a bunch of stacked up shields, the Gnd will be connected via the headers.

Thanks for the quick reply! I will make a list of the amount of pins I will need and hopefully be able to order a microcontroller this weekend.

Say I come out to needing more than 15 pins due to another sensor needed or what not, which controller would be next besides the uno?

Also, I haven't been able to find this but are arduino only able to process one thing at a time to where there will be significant delays? The robot we are doing has to collect balls on both sides of it (at times one needs to be collected on each side at once and we were going to put a light sensor to tell when there was a ball so the arm could swing and collect it. Just want to make sure that there wouldn't be too much of a delay between driving the wheels and using the two sensors and two servos at once.

Thanks again for the help so far

Depends what you mean by "significant" but if you are dealing in physical things like balls, it will almost certainly be able to react as fast as needed.

To notice a ball passing a sensor (or more than one sensor) should be achievable within, say, 10 microseconds, if not faster.