I got my 2005 frame for free ('cause I found it with nothing but a fork and bars) but all in all I'd say you could piece-by-piece upgrade it into a dang sweet sleeper for tops $500, especially if you score that Marzocci. Here's what I have on mine:
New Shimano Deore Shadow RD, $50
Used Shimano Deore LX FD, $15
New Shimano Acera M361 crankset, $35 (will probably upgrade to a Hollowtech set since I bent it dirt jumping)
New Shimano HG51-8aw cassette, $20
New Shimano Alivio 8-spd shift trigger set, $35
Used Shimano Deore Hydraulic brake set, $80
New Shimano BB-UN26 bottom bracket, $15
I got a RockShox XC30 as a generous donation from a relative, but that would only have been $150. Buuuut it's still just one of those works-for-now forks, since the RST it came with was absolute garbage.
and other stuff. $250 for all that makes for a boss bike, plan on a little more for wheels since you will need those if you want to go disc brakes (which, trust me, you do).
Building a sick ride is cheap and fun.