Test ride before you buy. I fit a women's Specialized Ruby road bike just fine, but the Specialized Safire (women's Stumpy) is a terrible fit. I ride a really small frame (I'm 5'3), but after test riding more bikes than I can count, I found my best fit to be a unisex bike (AS-R, which comes in size XS, as do many other bikes), so don't be afraid to test bikes that are marketed towards men. Come to think of it, all of my mountain bikes are men's bikes...I don't particularly like the fit of my hardtail (Fisher Tassajara, which I bought before I really knew how I wanted a bike to fit), but I've definitely played with other companies' men's hardtails and found them to fit me fine.