For beginning either IMAC or pattern you can fly whatever plane you want. No restrictions in the beginners classes.

for pattern maneuvers, check this out:
http://nsrca.us/documents/judging/cu...rtsman2007.pdf

Basic pattern homepage is nsrca.us

Just worry about safely flying the maneuvers and not so much about the plane. I started pattern flying a $99 Dolphin.

Entry level pattern planes are the Great Planes Venus II, Piedmont Models Focus Sport, World Models Spot On, and others.

As far as what's best, well, the best thing to do is go to meets and see what you like. I got hooked on pattern the first time I saw a guy fly a pattern ship through the routine, at my first pattern meet.