Boulevard Flowers is a bit expensive for my tastes, but they offer a large variety of plants for the gardener in us all. I like the fact that they have several cats roaming throughout the facility, as well!
Their gift shop is a fun place to shop if you have a gardener to buy for, and their florist offers many different potted plants, flowers, and balloons for those special occasions.
If you're looking for something in particular and can't find it at one of the discount department stores at the mall or the chain home & garden shops, take a look at Boulevard. You just might find what you had in mind.