both bikes that volvo posted are gonna be close to or more then 40+ lbs.
not very well suited for XC, but you say only a little XC so the heavy bike may not bother you very much.
Depends on your level of fitness and how much uphill riding you wish to do
whats your max budget? I find the the really really sweet deals on used bikes start @ around 1500 bux.
1/2 years old and typically in great shape.
One thing to keep in mind is that the older the bike is, the cheaper but also heavier its gonna be.
I just helped a buddy of mine buy a used bike... He picked up a 07 Hectik 2 for 1700 bux that was in fantastic shape and barely ridden.
Probably more then u wanna spend, and also more bike then u seem to be interested in, but there are great deals on used bikes.
Think at least 50% off retail for anything 1/2 years old.