"Best" is a purely subjective term. There are some distro's that are considered more friendly for newbies, such as Red Hat, Suse, and Mandrake. However, it is generally held that they are not as fast as distro's like Slackware, and especially Gentoo & LFS. If you want the most stable distro, it's hard to argue with Debian or Slackware. Fastest would probably go to a stage 1 Gentoo install, where you compile EVERYTHING for your own processor. If you want tons of software and GUI tools for doing everything, then check out Red Hat, suse, or Mandrake.
It comes down to choice and personal preference. Do you want the most stable? The fastest? The most easy-to-use GUI tools? You have to decide for yourself. Or better yet, do like I did. Get a spindle of CD's, burn about 5 different distro's, and try them out before deciding.
Now obviously, these are just my opinions, so take it for what it's worth.