I think that will be easier , because through camera means I have to do image processing and all other stuff.
Just so that we are clear, arduino is to weak at this stage to do image processing.
As u said, ur new to this platform and i dont know how much of electrical knowledge u have.
Now for first robot i would do something simple with 2 or 4 weels, first without any object detection, like here
Now u can use DC motors or steppers, stepper motors are a bit more advanced to use, but might spare u some problems later.
Now it depends what sensors u wanna use, Ultrasonic Module Range Detection like here
In this case ull need to proly use a servo as well.
Or u can use IR leds and IR receivers, in which case u drive IR leds with a NE555 timer at a certain frequency and when u aproach to the object close enought Ir receiver outputs logic lvl 1 on output.
Or the most simple way is with normal switches. like this movie (not made with arduino, but just to show concept)
Basic principle avoiding obstacles.
Now as ur new maybe do some tuturials, some usefull linkshttp://www.earthshineelectronics.com/10-arduino-duemilanove-compatible-starter-kit.html
at the bottom of the page( its free, the ebook i mean
or a bunch of tuturials, but i think the above 3 especially the ebook on first link is great, cause u might get a bit lost on freeduinohttp://www.freeduino.org/
I would recommend if u try to do some stuff out of that ebook, so that u athleast have some idea about coding and then go to making robot.
Btw maybe u should consider asking admin to move the topic to a more appropriate section