Gday Warlock!
The main reason I use the Client/Server method, is that I have a nice big fat machine in my room with twin 80Gb mirrored (soon to be full 240Gb RAID 5) array. This machine is reasonable grunty, and it's the "central" machine on my home network.
I have another machine in the lounge connected to my stereo system, with an LCD monitor (looks more like a piece of furniture than a CRT!!). The lounge machine is not a big chunky box, as I wanted it farily discrete in the stereo cabinet etc.
Also, when I have a party, with the mandatory drunken and off-their-dial friends over, they can access my music collection without me worrying about em doing harm to my collection's organisation. I also don't have to play DJ all night, people can use the interface with minor instruction, and everyone can queue up their favourites without arguments about what plays first etc. It's strictly first in best dressed; unless of course it's ME who wants something played NOW 8-) - Hey it's my toy, and I'll switch it off if you don't wanna play by my rules!!!
My better half also has a machine in her room, so she can be playing "studying" music while I'm blowing my eardrums out over the other side of the house.
It works really well, and I'm forever grateful that I decided to cough up the dough for this great product!
Hope this explains a bit about why it's a good tang...