Benjamin Moore paint is by far my favorite. You may pay a little more for this paint but it's quality paint that goes on easy with good pigment through out. Seattle Paint supply carries this line and they have all the supplies and customer care to help make your painting experience a positive one. If local non-profits come calling, they will donate paint from their returned stock.
Miller Paint in Ballard has a nice selection with their color line called "Devine" you can sort through beautiful color combinations that scream out at you to paint your whole house. But I don't like the customer service in this store, they cater a lot to painting contractors and once I got my ordered bumped because they serviced several of these guys ahead of me.
Stay away from paint like Ralph Lauren, which I think is by Glidden, sure it has awesome colors but you end up having to put on 5 coats to make good solid covering.