It isn't that straight forward. Mandrake is what i would generally recommend, though i haven't seen 9.1 and 9.0 was one of those "install, fiddle, find it's not all it could be, fiddle more, decided to compile a kernel, find that the software requiered wasn't installed when development was selected, decided to go back to a better linux" in short, i didn't like it too much.
SuSE i found good, but apparently that means i'm sleeping with the enemy because of SCO, nevertheless, it is a good distro and you get alot of software so you don't need to hunt arround the web for what you want to run, so that can be handy (now i run slackware which comes on one cd, and i know where to find the software i need in addition).
Generally, i would say go for a real linux distro, Slackware or Debian, they are hard to use (debian was like my first linux distro all over again) but you learn so much ... Slackware on the other hand is really simple to use (though i keep hearing otherwise).
In the end, go with what your friends are using, it's great to be able to get one to come over if you have a problem, but in the end, linux is linux, (unless you run RedHat) ... that's not true... think about it this way:
if you run slackware, after a while you will know how to run most other linux distro's, you won't know their distro secific tools, but you'll know where to look. Debian will do that for you also, but slackware doesn't equate to running into a brickwall at 100kmh, which debian does. Redhat and Mandrake and SuSE all have their own little faults which mean for many people they aren't an option.
Which is best? try em all.