Senior design project advice needed

Hello everyone,

Short version:

For my senior design project we need a microcontroller. I was told to look at the atmega## version from atmel but not know much about it, it is kinda overwhelming. The microcontroller needs to be interfaced with several sensors, control a few motors and do some AI. As you can tell from this next comment I don't know much about these things. I am assuming that all of these microcontrollers are capable of being programmed in C. I won't be to excited if I am going to have to do everything in assembly.
Any suggestions would be great.

Long version:

To give a little background story of what we are trying to accomplish in our senior design project.
Our senior design project is to build a search and rescue robot. We just got assigned this project and we are doing the initial planning stages of the project and that is why I am here.

Some information about the robot we are planning to build and some of the small criterias we have to meet.

This is going to be an outdoor robot that will be placed in a random location and scout the area for a certain object (orange traffic cone). This cone can be detected via sound, light, or some type of color sensor (its a design you have to figure this out). Once it finds the object, in this case the cone it will then relay back wirelessly a GPS location. You need to be within 3-4 feet to be considered successful.
If something wasn't clear please let me know.

This was given to us.
Well the group is currently in the planning stages of this project. We are all doing research on what we need to do to start making this project happen.
Our groups are broken down into locomotion, controls and sensors. I am personally in the controls group. The reason I am here is I am looking for some type of microcontroller to tie everything together.
Currently locomotion is currently looking at using tank tracks for mobility. Sensors is looking at using sonar for obstacle collision detection and some type of color sensor to detect if it is an orange cone. Again this is all in the planning stages so everything could change. As for me I need a microcontroller to tie all this stuff together so I would like some advice on what microcontroller to get and use. I have never used any type of real microcontroller for anything so I am not really sure what is involved with one these things.

I was told to look at the atmega## versions. Would this be a good place to start?

Any suggestions would be great.
Thanks.