tim,
i've use quite a few linux distros and while they all seem to have their quirks, I've settled on gentoo.
debian was fine, but I really wasted a lot of time configuring. redhat will work. suse is probably the worst of all selections. I also played round with some minimal linux's like crux.
in the end, I'm sticking with gentoo. config is simple but can take a while to understand the system. when installing though, be prepared to let you computer sit for a day or two. it really takes a while to compile gcc, xfree and mozilla. not sure if it really speeds up the machine, but it really feels faster (at least psychologically).
for pd though, you probably will run into problems with alsa and jack and pd. expect to download these apps yourself and install in /usr/local. and the pd dist is stuck at 0.35 I think at the moment.
I've always had a symstem, even with debian and redhat, that was a mixture of 'core' distrobution programs and then self-compiled apps (normally alsa, mplayer and the media things) in /usr/local. with gentoo, i seem to be doing the same.
maybe that helps -august.