My 911 is an '80.
There are plenty of things that you can do on them yourself, and none of it is really too complicated if you're patient (which I'm not, so the shop does engine/suspension stuff)
Parts are hit and miss, some things are really cheap, others will kill you. There is quite a big used/dismantler/BBS market though, so a lot of stuff can be found if you're willing to look.
For instance, knobs on the interior, $3, fog light lenses, $6, power window switches, $15, new distributor, $900.
Mine has about 150k on it, and I drive the hell out of it when I'm in it and it's held up just fine. Just had a friend spin a bearing on his '81, but that was after 150k+, unknown maintenance of previous owners, a year and a half of hard driving since he's had it and it's 6th track day. Everyone was actually even a little surprised that it let go, there aren't usually too many big problems.
But, that might be too much of a $$ commitment, so how about something like a 924? Not the prettiest, and not all that fast, but can be had <$5k, and are very well balanced and fun for tossing around.
http://cgi.ebay.com/ebaymotors...VWQQrdZ1QQcmdZViewItem
My first car was an '80 T-Bird, and while it wasn't the best body design in the world, I had a lot of fun with it and it was easy to tinker on.
Another idea, if you're brave and have a lot of time on your hands you could look for an Alfa Spider convertible. Fun cruiser, Italian sound and design, pretty decent motors once you get them figured out.