After just buying a new full suspension I would completely recommend riding and if possible renting bikes you are interested in. I thought the Specialized bikes were the best for me based on the parking lot test ride, until I took one on a trail and discovered the cockpit it was too compact. I ended up ordering a Gary Fisher Hifi Deluxe GS which I was cautioned many hate the geometry. Well, I love it. I was lucky that my LBS rents the Specialized Safire and gives a one week guarantee on bikes. Since I couldn't rent the GF I was given the piece of mind that just because it felt magical in the parking lot it didn't mean I was stuck with it. Luckily, I love my new bike.
With your height you could easily get a men's bike but you should look at every option before spending your hard earned money.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan