Hey,
If you really want to spend $700, you can probably get a little better bike than the 4900. I almost bought the 4900, but after shopping around, ended up with a Gary Fisher Tasajarra. This ran me $560, and the model with disk brakes is probably about $50-70 more. Have you looked at the Trek 6700? From what I remember, that is under $700 and has a little better componentry, although I'm not sure of all the differences.
I don't know too much about bikes, but having shopped around, some other bikes you might want to look at: GF Tasajarra, GF Hoo Koo E Koo, Specialized A1 Pro FS, to name a few. I'm sure others can name many more in this price range.

As far as suspension goes...you can get a better hardtail than a full suspension in this price range. If you go full suspension, you're gonna end up with lower grade componants to make up the price difference. You'll probably get a low to decent quality frame, suspension package, and componant package, where as with a hardtail, you can get a good all around package for well under $700. For what you're doing, it sounds to me like a hardtail will be more than enough...mine has taken a beating and is doing great.

Good luck with your bike search.

John