Gap jeans fit me well, too. I just started buying them in the past year. I also bought a pair of really nice black stretchy pants for work.
Loft and J Crew petites fit me well, also, but you need to know which style is best for you. With J Crew, I can't try on in the store, since they no longer carry petite sizes in the store. But, I generally stick with one style, once I find one that fits.