Look in the YELLOW PAGES under PAINT - RETAIL for a paint retailer near you. In my area, I'm partial to Finneran & Haley. Benjamine Moore and Sherwin Williams are excellent paints too.
As an aside, many, MANY paints made for sale in Home Depot, Lowes, Wal-mart, and places like that are made by the same companies (among others) that I just mentioned. The difference lies in what's in the can. In short, if the paints were the same, then the Paint Retailers wouldn't be in business. The vast majority of Painting COntractors use the paint from the Paint Retailers because 1) they get credit there, and 2) the paint is good enough that they know they won't be getting called back to the job site due to 'bad paint', and 3) that's where they've been getting their paint for years and years.
Certainly, you can take your chances with the HD, Lowes, Wal-mart, and other brands. 1 story for you: A neighbor 2 doors up from me painted his home with paint from Rickel's (which went out of business in '96.) Two years later, he was painting the outside of the house AGAIN. What do you expect for $7.99 a gallon??? AND, Rickle's is making a profit on it as well as the mfgr.! THAT has to tell ya something. (And this 'subject' of Paint Retailer vs. Big Box Stores has been beat up on this Forum.) Well, 'nough said.