Hi and welcome to AVD Forum....
You will probably get many difference answers to what is the best model Beetle....
I have found that the early beetles are usually more rust free than their late model buddies....
I Myself like Beetles from 1968>on...
they have disc brakes... [most of them]
Ball joint front end..
12 volt electrical system...
then there are the non super beetles...
and the Super Beetles... 1302 with flatish windscreen
and the 1303 with large curved windscreen
You need to check around the rear window... for rust
also check the heater channels which run from the rear mudguard to the front mudguard.. on each side..
bottom of the doors and near the lower door hinges inside
also check around the rubber seal in the front boot and around the engine bay, under the engine lid...
also don't forget to check under the mats front and rear.
Rust can be a Major issue.... depending on how the car was looked after... if you can find one that has been garaged all its life... the car Should be in great condition..
Best of Luck
You should fill in the details under your user name so We know where You are, city, state etc...
Lee Noonan - 68autoBug -- NSW
http://community.webshots.com/user/vw68autobug