It's great that you are taking an initiative in building/replicating one like EZ-Robot. I would like to add few things which helps in building a robot.
Simplicity.
Cost Factor.
With Simplicity I mean, choosing the right most hardware that actually helps your prototype to be built faster and the testing/debugging is easier. For instance if you choose: Raspberry Pi with wifi module (I saw one at adafruit stores for around \$12), the whole setup may be build under \$50. Adding Computer Vision (I think this will boost up the investment price) since it already runs Linux on it, helps in achieving the ease in usability and development. Now you have a system that can be controlled by many components. Using a bluetooth module with Rasp Pi is much cheaper than you may think. Chinese modules are cheap like \$5-\$10. Hereby you will have an independent robot.
But as you say, you wish to remotely control, the arduino keeping your PC(Since you mentioned Visual Studio), this can be done easily by adding wifi module but Xbee cost's are really high, and then use the http protocol to control the robot. The arduino will be fed with some input like say numbers ranging from 1-100 that may accumulate 100 tasks. Like move left, right, up down, turn on the light etc.
So essentially make sure, which development board may help you serve the purpose easily.
