I'll give gentoo this: it's a LOT of work initially to get a very tight, low-maintenance system later on. Portage lets you specify exactly what features you'd like to compile into each package, so if say mozilla or OOo has an optional gtk enhancement, you can choose whether or not to include it when you compile it. You get to choose what optimizations you compile with as well. And if you're not comfortable with this or don't have the time, it gives some pretty decent defaults.
I'm using gentoo now, and I have to say that there are no forseeable changes on the horizon. I've never had ANY system so finely-tuned to my needs. Exactly what I want to include goes in and nothing else, and everything I include includes support for what I want it to include. I'd highly recommend Gentoo for someone who has a weekend to throw into getting the system how you like it (another one of the downs: compiling things like OpenOffice takes over a day...so does KDE, and X, Mozilla, Gnome and GCC aren't exactly sandwich-break material either).