Disclaimer: this post does in no regards say that a distribution is better than any other; I'm not looking for a flame-war, I'm just stating my own personal opinion on what lead me to use the distro I use today.
It's true that when I used Ubuntu I didn't have the knowledge I have now, but it felt to me like compiling (eg. pulling all of the dependencies for a package was quite a hard thing to do, since the source packages were separate), that was the reason why I starting looking for an alternative. Of course I came across Gentoo, which is basically a compiloaddict. The problem with Gentoo was that in order to compile big packages, openoffice (before it became "libre"), kde, wine, firefox, etc, you needed time and a lot of CPU cycles. So although I felt that Gentoo came really close to what I wanted in a distro: few default packages, up-to-date, complete control over the system eg. the ability to customize everything, easily, etc; it simply wasn't worth all the wait for them (the packages) to compile. Also Gentoo didn't work out of the box, which although I didn't have no complaint over was still an extra step in making a fully functional system.
A lot of the distros I tried satisfied many, but not all of what I wanted:
Fedora and SuSE for example were packed with new packages, worked out of the box, but they felt bloated as they had a lot of packages installed by default. Many of them I had no interest in (bluetooth manager), but others such as SELinux started automatically and that meant reading documentation about how it worked and how to configure it.
Slackware on the other hand, although seemed good at first, didn't supply new packages.
So, after looking on distrowatch.com for my next distro to try out, I came across Sabayon: