I love Green Thumb, they have so much variety and the plants are so much stronger than when you buy them at a home improvement store. Also, the ladies there know everything about plants, and give great advice. And, last but not least, they always send me coupons as I subscribe to there weekly email newsletter.
Pros: very knowledgeable, wide variety, send coupons
Cons: a little pricy, but you get what you pay for