You can get a pimpin used mountain bike on ebay for $1000. Giant is usually the cheapest, if you are new to mountain biking I'd suggest a full suspension NRS Air. If you are lulcky you may be able to find a Specialized Epic or Trek Fuel 90 for around $1000 with Shimano XT components. If you were a skilled mountain bike rider I'd tell you to get a hardtail, as you can get a great bike for $1000, but since you are asking the above question I'd say a fully suspended rig is for you.

Like this bike for $1250 is a steal:

http://cgi.ebay.com/...QQrdZ1QQcmdZViewItem

yes. there are tons of competent mtn bikes in this price range. since an xterra bike is a mtn bike (it has to handle like a real bike after all) any decent mtn bike will do. you could even get into a pretty good full suspension at that price ... ie santa cruz superlight. id say look for a solid aluminum frame hardtail (no rear shock) w lx/xt level parts (more or less equivalent to 105/ultegra on the tri/road side). trek, specialized, cannondale ... all will have something that fits the bill.

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"In case of flood climb to safety"

That bike looks good but isn't 30 pounds a little heavy?

With mountain bikes, you pay mostly for weight reduction and a little for technology (disc brakes, "smart" suspension are more expensive.) For $1000 you're looking at a 23-25-pound hardtail or a 30-lb bike with full suspension (depends on the size of the bike of course.)

All the FS frames weigh in the 5 to 6 pound range, so the price varies based on the fork, wheels and groupset. Mavic Crossmax wheels, Rock Shox WC fork and XTR group will get you down to 25 lbs in a dual suspension bike, but not for $1k.

if you have never ridden a mountain bike before then the Epic will be PLENTY of bike for you.