AdamRandall, some of the "best" effects are actually rack-mounted. Couple of delays and reverbs especially come to mind. Also, there are many people who put all their effects pedals into shelves in a rack, then use a patch bay and a MIDI controller in order to access all of those.
If you're playing frequent gigs, never change your settings, have cash, and possibly a roadie or 2, these can be quite nice. For example, John Petrucci of Dream Theater uses a custom switcher to access all his gear. To change from song to song, he hits the "Next" button, and all of his buttons are ready to go for that particular song. One button could also activate a massive number of effects, saving the need for the "pedal dance" most of us are accustomed to.
So, depending on what you do with your effects, a rack system can either make your life simpler, or much more complicated.