Hart's Hardware is the kind of place that makes being on the North Fork worth while. You will not get this degree of service anywhere else. They've got a great collection of tools and home-improvement supplies, it's well-organized (for a hardware store), and the employees are more than eager to go out of their way to help you find things and make your life easier.
I've been shopping here for years and can only say good things. The owner and family are intensely friendly. They know me by my first name (even though I'm not sure how, lol). They will give you advice on how to repair just about anything and the best part is, when they don't have the answer, they admit it! They don't try to sell you some piece of crap that won't do the job.
Sure, you can always save a tiny bit of money by spending 30 minutes each-way in the car (Riverhead) and buying your shitty spray-paint at some box-store. The truth of the matter is, though, you save money by staying close to home. Shopping locally saves on gas and allows you to get things done QUICKLY! I've done some comparisons and Home Depot was not cheaper than any of the items I bought at Hart's. Plus, I prefer the atmosphere at this little place. It's great.