Hey Mav.
everyone has a different opinion on which beetle is the best....
I like 61-66 due to the fact of simplicity and you can repair them yourself once you become familair with the car.
I've owned several VW's and my favorite year is 1961....due to the fact that in 1961 the transmission was switched to all syncro gear...meaning that you did not have to come to a complete stop to put it into first gear, otherwise you would grind first gear.
as far as power, make sure the beetle has been converted to 12 volt and is running at least a 1600cc dual port motor. if you find anything bigger with your car like a 1776-1835cc then great! If you want to add a little pep to that 1600 you can do bolt on's like dual carbs, rockers and header exhaust system or go all out and invest in a new motor.
When looking for a beetle dont buy anything with rust in the rocker panels or anywhere else that would be hard to replace.
this is the best place to shop for a car and get great advice.
http://www.thesamba.com
good luck
Ed