start with a porter cable IMHO. As that is what I did and the new one has godo amount of power and versatility. There is a really good kit from Autogeek.net, and has everything you could need, this is about the same that I use and would recommend to you. Also Meguire's G110 V2 polisher is very good. Mix it with some new Hydrotech pads and good microfiber towels and your set up for perfection. PM if you want to discuss these more.
Dual Action Orbital Polishers and pads: Porter Cable 7424 : Porter Cable 7424XP: Lake Country Buffing Foam Pads