This is just my list, lord knows there are millions of others sites we check everyday. If you have a few favorites that are not included, shoot them my way, I would live to add them to the list.
Site to Add:
I also may have missed a few sites that are no longer active or have moved URLs for whatever reason. If you come across a vendor or forum no longer in action, let me know, I'll get it cleaned up!
No Longer Active: