Before I discovered Cohen's Optical (see other post), I shopped at Lenscrafter's for a long time. They have a big selection, but their biggest advantage is price. They have frames spanning a wide range of prices from extremely cheap to very expensive. You can usually find additional coupons or discounts that reduce the price even more.
While the selection is big, I was never able to find frames that I really really liked, instead having to settle for the best one I could find.
Another big advantage is that you get your glasses within an hour instead of having to wait for a day or come back another time.