I've been lagging behind on my posts (sickness, end of semester and holiday rush, etc.), but I hope to correct that very soon.
In the meantime, here are a few good sources of photoshop brushes to keep you working on the Monthly Special:
Smashing Magazine as a list of 50 must-have photoshop brushes
Photoshoproadmap lists 100 brushes (you will begin to see some crossover between lists).
Qbrushes lets you browse a decent selection by category.
Tutorial blog has a list with some good ones.
The talented Eduardo Recife shares some great brushes (under "goodies") and fonts. No previews, so you will just have to trust me that they are worth the download. And while you're there, check out his art. I love the handmade (i.e. no Photoshop) collages (see Illustrations--> Collage Book 1, for example).
and finally, there's the massive collection at deviantart.com.