I have shopped around at the different garden centers here in the area and I find Armstrong's to be the best. The people who work there are helpful and patient and seem to love doing what they are doing. The quality of the plants I have from there are so much better. They don't die within the first couple months as so many plants have that I bought from other competitors. Even if Armstrong's if a farther drive for you than a 'comperable' garden center, it's worth the extra drive.

This place has a wide selection of plants, fountains, fertilizers, and even free classes. Staff is knowledgable. And they have a lifetime guarantee-- save your receipt and if your plant dies they will give you your money back. I haven't taken advantage of this yet so I don't know how strict they are (what if you just didn't water it?)
They are slightly pricier than a home depot or a target but these plants thrive better in the same conditions. I have a lavender from here and one from Target and the Armstrong one is twice as big.
Also, if they don't have a plant they will order for you.

PROS: Lifetime guarantee
CONS: slightly higher price