I was a professional baker (and cake decorator) before I enlisted into the military. Hopefully I can share a few tricks of the trade.
I agree with Riley: No-name heavy duty pans from the bakery supply/restaurant supply are the way to go. You really only need one size sheet pan. Bake off a full sheet, and then cut it down into 1/2 or 1/4 sheet cakes....freeze the rest for later. I also buy my sheet pans from Sam's club. They're inexpensive and heavy duty. Buy parchment paper and sheet frames to use with your low-edged sheet pans, and buy springforms for your rounds. Lay the parchment in, then the frame, spray with baker's release (this is an oil/flour blend spray). Don't use Pam or Crisco if you can help it. I think they sell one called "Baker's Joy" at regular stores.
I don't like Wilton. I never use teflon/non-stick pans.
Lopsided cakes are not from your pans. It's from your oven. Uneven heating/baking causes uneven cakes. Opening your oven often to check your cake will yeild uneven baking. But whatev. It happens. It doesn't really matter if your cake is uneven if you prepare it properly for icing.
Before you ice your cakes, freeze them. Then use a cake saw to slice them in half horizontally. Flip over both sides so that, after you fill your middle layer, the bumpy top is now inside the middle of the cake. If it's REALLY uneaven, you might have to do some sculpting. Just use a sharp knife or cake saw. The top is as going to be as smooth as you cut it. Then finish with a sharp knife to cut the edges to a 90' angle.
If it starts thawing out, put it back into the freezer before you start icing it. Frozen cake is MUCH easier to ice and decorate.
Best of luck!
C. Lee