Classic 26" mountain bikes don't get a lot of love these days. I think that's somewhat due to the popularity of 29ers and MTB's fitted with disc brakes having pushed the 26" MTB's aside.
That having been said, it appears your bike has the XT group like the MOMBAT bike does. That group alone is probably the best thing about this bike. Some folks still swear by the XT thumbshifters, for ex.
If it were a steel frame, it might be a little more popular, but this one is aluminum and welded.
Around here, maybe $125-150 completely fixed up, needed parts replaced, tuned, cleaned and ready to go.
I think you could do better parting it out. You might get that much from the XT group alone.
As always, your market may vary.