A: The most expensive you can find.....with a caveat
There are scenarios (even in extremely low profile job scenarios) where it pays to go with the most expensive paint available. It will ultimately save you money. One of these scenarios is using deep base colors on accent walls.
Bright Reds, Dark Green, Royal Blues and other deep base colors will not cover in two coats (even if you tint a quality primer) if you get cheap paint. You'll end up spending a lot more time with 3, 4 or 5 coats then you otherwise would if you simply would have got one of the two products. 1. Benjamin Moore's Aura or 2. Sherwin Williams' Emerald. Both Products are selling around $70.00 retail. A good painting contractor can do considerably better on that price but these products will generally cover in two coats (with primer and sometimes without) in any color and they are largely burnish resistant to boot.
Here is a job where a homeowner picked up the paint for an accent wall for us. Generally I always buy products but on this particular job the homeowner was insistent on purchasing the paint. We primed the walls with a dark grey and ended up applying 4 top coats:
I didn't charge the customer any extra money because there was other work to be done as we allowed this paint to dry but had the homeowner wanted an entire room painted with such a poor product it could have cost him a lot more.
You can see from the pic that after a patch, primer and two top coats its not even close to a finished product. Stick with the top of the line products for any deep base color...
Nick Dettinger
Complete Custom Painting
651-336-0561 cellular