Buying a bike is such an individual decision - my only advice is to not rush into something or settle 'cause that's all there is.
For the record I ride both a hardtail and a full suspension bike. I like them both, equally. They serve different functions. The hardtail is lighter, quicker more responsive and climbs like a goat. The fully is heavier but allows me to take tough descents alittle easier. I ride the hardtail when mostly doing fire road and there's alot of climbing. I also use it on flatter, quick single tracks. I use the fully on singletracks, trails with steeper, gnarly descents, when I need a smooth ride etc.
If your money is limited, I suggest you get a good hardtail. If you have some money to spend, then consider a good "all-mountain/cross-country" fully. There are alot of good brands out there. Rocky Mountain, a Canadian company, makes a good bike. I love the Specialize mountain bikes (my hardtail is a Specialize M4 Stumpjumper) but the newer Spec. bikes are not as good as some of the older bikes and the price has gone way up. Trek makes good road bikes but I am not convince they make good MT bikes. I've heard alot of complaints.
Check around for these: Cannondale, Turner, Santa Cruz, Ventana, Ibex, Gary Fisher (my fully is a 2002 Fisher Suger 3+), Kona, GT, Giant, Titus and Rocky Mountain.
Try and ride each fo the bikes you want. Don't assume you need a bike with WSD geometry. WSD bikes don't work for me. It works for a woman with longer legs shorter torso. And don't assume that since you ride a small/medium you ride a small/med for all bikes. Geometry is different with each one. Make sure the shop is measuring you.
Good luck and take your time. Do some online research. Check with your bike friends. maybe they have a bike you can borrow and ride.