Well, for starters, $600 and junk components usually go hand-in-hand. Maybe not walmart junk, but pretty much the bottom of the barrel.
If I were you, I'd get something like a Redline D440 that has a rigid fork. Since you'll either be on the road or mellow trails 90% of the time, rigid will serve you much better. You should be able to get one for less than $600. If you're really brave, I'd suggest getting a rigid singlespeed, like a Redline Monocog or GT Peace. Tons of fun.
If I were you, I'd get something like a Redline D440 that has a rigid fork. Since you'll either be on the road or mellow trails 90% of the time, rigid will serve you much better. You should be able to get one for less than $600. If you're really brave, I'd suggest getting a rigid singlespeed, like a Redline Monocog or GT Peace. Tons of fun.