Free Stuff

VST(i) / AU
mda-vst.com has vst and au's
Kammerl Audio a pack of five effects for Windows and OS X
Antress Modern Plugins Windows only racks
Free VST's from Andreas Ersson
DSK Music make heaps of free VST's

Lists
Free VST(i) list from electrobel - HUGE list
Free Samples from IDMForums - HUGE, but you must be registered to see links
Free VST - Old dead site
Free Music Software - The new home of Free VST, also has software and samples
Free Plug-in List - Reasonably good site
Best VST Plugins - links to download some vst's

Everything
Dont Crack has heaps of freeware for Windows and OS X
Studio Toolz has heaps of Mac freeware

Misc.
KVR Audio is great for information on everything audio
Rekkerd Audio Software news
This Is Not A Label videos and links to interesting stuff

I will update this when I remember more links.