In the toolbox of every professional Web designer you'll find high quality Photoshop brushes - and in some instances, you'll often find hundreds. I've taken the liberty of identifying some free resources I have been using lately to download brushes (although I would most certainly not consider myself a professional designer). What I've found over the past few weeks is that trying to put together a personal list of "favorite" brushes is sort of an arbitrary process, and each design scenario requires a different perspective and in turn a different design brush. That being said, many of the sites listed below act as excellent gateways to the best Photoshop brushes.
Brusheezy is a site for artists to download (and even vote on) custom Photoship brushes and patterns. Sister sites of Brusheezy include vecteezy (free vector art) and flasheezy (free flash files), which are both worth a look.
Some sample brushes from Brusheezy.com:
GetBrushes is another resource for finding quality Photoship brushes. The site is well organized and many of the featured brushes are free for non-commercial work.
Some sample brushes from GetBrushes.com:
BrushDownload is the final brush download site featured today. Not well organized, but there are actually quite a few gems to be found here and the number of downloads for many of these Photoshop brushes clearly indicates that.
Some sample brushes from BrushDownload.com: