you can also run those from usb (provided motherboard allows this) to save discs... and ubuntu can be tried from web to save download times and such. Debian is also moderately popular compared to the others, and Ultimate Edition seems to be like others, but with more preinstalled software.
after you get a bit more accustomed to the linux environment, check out http://livecdlist.com/
for some other options. most can be run from a usb stick, so besides download time, they wont cost you anything to take em for a test drive.