bruinlad
Adventurist
I'm looking hard at pre-owned Giant hard tails right now.. Mostly because the $$ is right for a used one.
Since you're looking at Giant bikes here's something to consider. These are mainly for xc style riding designed to behave like hardtails so there's no bobbing when pedaling but still reacts to bumps thanks to the design of the rear shock and suspension. Google Giant NRS (No Resonance System) for more info. I still have 2 of these from 2002 and still ride them from time to time.
Here's an NRS 2 on CL in Yucaipa. Good bike for the price and fully upgradable frame and if this came w/ the wheelset it was sold new with then they are disc brake compatible as well (see bikepedia link). I would still negotiate on the price though.
http://www.bikepedia.com/quickbike/BikeSpecs.aspx?year=2004&brand=Giant&model=NRS+2
http://www.mtbr.com/cat/bikes/xc-suspensio/giant/nrs-2/prd_363243_1526crx.asps
http://inlandempire.craigslist.org/bik/4395349075.html