I found a cool website recently that any aspiring songwriter should check out. It's called "looperman.com" and basically acts as a hub for people to share sound/music loops that they have created. Registration on the site is free and so are all the loops. They can be used privately or commercially, with only a credit required.
Of course, since virtually anyone can upload loops, you'll find some things that are useful and some that are not, but as I've skimmed the surface I've so far found most loops to be of good quality, if not always what I'm looking for.
Currently, I'm looking a for a little electric guitar material. I've got a friend who did some great guitar work on one song in "Dark Ritual" already, but when I need something short, simple and repetitive just to "fill-in" the sound some, loops are a quicker and easier way to go.
Currently I'm working on a song for Dark Ritual called "Death Come Quickly". Like one or two other songs in Dark Ritual, it has an Epic feel, so I'm looking for authentic sounding strings and will also add choral voices using a mix of samples, synth and my own voice to create the final sound.
Anyway, that's all for now. Back to work!