I Would not buy a Ubuntu computer for the following reasons:
Ubuntu does not work with Microsoft Word. You will not be able to do college work on it, if that is why you are buying it. You will end up going to the computer lab everyday anyway.
Ubuntu does not work with Verizon High Speed Internet. There was a news story about a girl who tried to install Verizon onto her Ubuntu Dell and it did not work! It was a disaster and she got kicked out of college for it because she couldn't complete her online classes. I would sue, if I was here! See: http://www.wkow.com/Global/story.asp?S=9667184&nav=menu1362_8_6
Linux is mostly an operating system used by HACKERS. This is what my nephew told me, so I wouldn't trust it--you'd probably have more problems with viruses and trojan horses.
If you do not know what oyu are doing you should use Windows--UBUNTU is very much in beta, which means that it is not ready for the public yet .I would wait until they have finished programming it.
JUST MY TWO CENTS