I mostly ride trail and enduro with a little downhill mixed in there too, moneys not a problem for me and im looking to replace the avid that came with my bike. what brakes should i buy?
Seeing as money is no problem why not buy a few different ones and see what you like best. Then sell the ones you don't want. That being said, xtr trail are the bomb.
Formula RO, SRAM Guide RSC, Shimano XTR Trail, Hope Tech3 E4 (or V4 with non-braided hose) ...
That said, I would probably go for the Guide. I'm not a massive fan of Shimano (although I run a set of Saint m820), I will soon try a mod on a set of Formula RO (love the brakes, but lever is too far from the handlebars to my liking, so I ordered a shortened pushrod, will try that soon), as for the Hope, they are utterly reliable, but lack some power compared to the other ones.
Try a set of hopes. Longest lasting, highest quality brakes ever made in my opinion. I run the race e4's on my covert and they're phenomenal. Some might say they're not the lightest or don't have the absolute highest stopping power possible, but they are only marginally beat, by say, saints, in the power category, or xtr in the weight. But they will far outlast them and will require far less maintenance. I have a brake from 2004 that has never even been bled and still works flawlessly.