I'm not sure about some of the advice here... it will work, but it seems odd to me to learn J perms when you don't know A perms. Again, it works, but I don't see it as being optimal. Here's the order I'd start with:
1. A perms. This will allow you to do corner cycles. Since you already know U perms, just learning one A perm will allow you to solve PLL. Learning both A perms will reduce the effort.
2. Learn Y perm for swapping diagonal corners. You can do this with E perm as well, but it lines up on the cube differently, and I think it's easier to see with Y perm.
3. Add the Z perm to complete the pure edge permutation cases.
At this point you'll have a true 2 look PLL.
From here on it's a matter of preference. I tried to learn the PLLs by learning the most frequent cases first, but I didn't base that on any hard numbers; just on what I though I saw while solving. So if I saw Js come up a lot, I learned J perms, etc.
Brian.