Q Alright, so I can make Gnome or KDE basically look like whatever I want it to, and I have hardware that's supported in every distro I've looked at. Aside from the package manager, what should I really be looking for in a distribution? From my standpoint, it seems that many distributions are very redundant in their features, though logic tells me that if this were true, they would not have been created. What should I be looking for? When you are running the same desktop configuration, do different distros differ much in performance? I've been using Ubuntu since I started with Linux, while distro hopping with a second partition, but I don't have the knowledge to tell whatworks best.
A To an extent, you are right. The heart of every distro is the Linux kernel, and that's the same for every distro, which is why hardware support is fairly consistent across distros. Some may use a more recent version than others, and some patch it to add a few features. The same goes for the included software, a distro may apply their own branding or theme to KDE, but it is still KDE. What the distros do add are administration tools, which includes but is not limited to the package manager. So SUSE has the all-encompassing Yast, Mandriva has its Control Centre, which is a gateway to many smaller configuration tools they have created, while Fedora and Ubuntu have their own selection of configuration tools (and Gentoo has Vim).
There are other differences, such as the way in which updates are released. Most distros only release security updates for the software bundled with a distro release, and if you want a later version you need to upgrade to a newer distro release. Ubuntu provides an option to upgrade an existing installation to the next release without re-installing, whereas a complete re-install is usually the preferred option with Fedora and SUSE. Most distros are community releases, and the community is often a distro's strongest asset. Look at the mailing lists and forums for any distro you are trying to see the level of support and assistance available from the community, which is an often overlooked factor when choosing a distro.
In the end though, it's all about personal choice. If you are happy with your distro, stick with it. If you get frustrated by missing or outdated software or unhelpful forums, look elsewhere. If you get the itch to try something else, do so - it won't cost you anything to try. However, you will learn more about Linux in general, and your distro in particular, if you stick with it instead of installing a different one each time you hit a snag setting up your webcam or you don't like the desktop wallpaper.