So I've been researching bikes for a bit and it would seme that I have somewhat of a pool of potential bikes lined up. I would like to pay as close to $300 as possible but am looking within the range of $300-$500.

Some things I know:
Id like a hardtail both for cost purposes and riding prefference
Disc brakes would be a plus, though not required
Ill be using it for riding in the woods, minor level downhill, DJ, and commuting under 5 miles

So far the feild consists of (In no particular order):
Specialized P series Condition: Used; Year: 2000-2004;
Specialized Hardrock Condition: New or Used; Year: 2003-2006;
K2 Zed 1.0/2.0 Condition: New; Year: 2006;

I was just looking for advice on any or all of the above bikes or suggestion on other bikes to look into. I like the more extreme frame design of Specialized, I suppose a shorter wheel base is what Im after. Just looking for a nimble rugged mountain bike really, a sort of jack of all trades if you will.

Thanks for any help.