I dont want to say its the best, but Ive been using Debian, Ubuntu and other APT based Linuxes for years now. Ubuntu on desktop PCs and Debian on Servers
Read the blog here
An example is the major security hole Debian/Linux as had this weekend – to update I done the below:
apt-get install linux-image-2.6-686 (to update kernel)
This one simple set of commands updated all the programs within my Debian install to latest release, and also replaced the bad kernel in the above bug.