Hey Tim, what's your budget? If you are ok with spending for a Veritas/Lie Nielsen, you can get a couple planes that will come to you ready to work as finely tuned specimens right out of the box. Otherwise you'll have to spend some time fettling and learning a little bit about what makes a plane great. And either way you'll need a sharpening set up that works for you.
If I had to pick 2, I'd pick a low angle block plane and a jack plane. Any jack plane would do, but a low angle would provide some extra versatility.