Meguiars Gold Class or NXT are probably the best over the counter. Check out www.autogeek.com
if you want to find some great boutique stuff. Some is expensive, but most of it is reasonable.
But before you wax, I would recommend getting a clay bar kit as well. You can find Mothers or Claymagic at any auto store. Just use it per the directions after you wash.
As far as scratches, you can try Scratch X. But more than likely you would need a polisher and some polish and/or compound to get them if they are very deep.