GlassJaw
Hero
I have yet to find a brand that has much of a shelf life after opening; they all dry out without constant use.
I bought a complete set of Vallejo Game Colors and have been using them for close to 2 years and I've yet to have any of the dry out.
I use your typical (and much cheaper) craft store paints with brand names like FolkArt, Apple Barrell and Ceramcoat.
The only thing I use those for now is for bases or terrain. I tried to use them when I started and I felt like I was fighting the paint all the time. They are terrible for mixing and don't their pigmentation breaks down when doing washes. I also found them to go on very thick and uneven.
After the person, the paints make all the difference. Even a very good painter will be hamstrung by inferior paints.