Linux Distros

What is the best Distro to run and why?

Really, I'd like to know why many of you hate Ubuntu so much. I've been using it for a long time now and it does everything I need, giving me an easy-to-use secure Linux distribution that ``just works". What exactly do you believe I'm missing out on? Is the much-heralded "Gentoo" really worth compiling everything from source for?

I've been reading and trying to go through Linux From Scratch (LFS) to learn more about linux, but after I learn about all of that, does it really matter if I use Ubuntu or not? How fast do you really need an average computer these days to go, and is the little bit of extra speed really worth it?

tl;dr
Best Linux Distro, and why. Is the Optimization really that important?

Also, as a sidenote: any advice on customizing Linux with certain additions and tweaks (like RatPoison as I've heard mentioned before) would be great. What are some really useful tools that aren't already given?

I run Ubuntu on laptops and machines that I'll need a tainted kernel for, Gentoo (or OpenBSD) on servers, and various things on everything else. Desktops usually have Debian or maybe an LFS if I'm bored.

Having used Debian and Gentoo for servers, I can say that the optimizations make a very big difference. I've also felt performance boosts on machines that have continuously high load after moving to Gentoo.