Actually what you like best can be optional... some distributions, for some reasons, have problems in recognizing some hardware components, so maybe you'll be forced not to choose the one you like more, but the one that works better in your computer, even if you don't like it at all
So I agree with Michael's suggestion to get some LiveCD and test them before to install a distribution :iagree:
Believe me... it happened to me with every version of Ubuntu/Kubuntu... there was always something not working :sad:
A rather frequent problem with Linux distributions is that ATI video cards have a higher probability (it is not a certainty, but it is very frequent) to be not working correctly, while nvidia cards drivers are working better.
You can read some more detailed information on major distributions and their derivatives here