Which car would YOU buy and why?

A 912 would be a good, usable choice, although again the money in these cars is all in the body work. I think that in most cases prices are based on how good the metal is. A 911T might not be hugely more expensive, but could be rebuilt to essentially RS levels of performance while looking original.

Here's one close to your photo:

http://www.europeancollectibles.com/inventory_detail.aspx?@page_inv_id=Po2491

 

I would probably buy an e46 M3 vert.

 

The problem with the 2.7L series is that you can get the much more durable/reliable 3.2L cars in the $20K-$30K range. So yes, the 2.7L cars can be rebuilt, but the market doesn't support it. (Turbos are a different animal...)

After '73, you lose the simplicity, lightness and cleaner styling of the original 911s as well and get the accordion safety bumpers, slightly increased weight, reduced power and ugly interiors.

IMHO, the sweets spots for Porsche were:

1956-1958 356A -- the classic Porsches; VW mechanicals had been replaced by Porsche mechanicals; Speedster-Cabrio-Coupe range

1964-1965 356C -- best-to-drive of the 356s, disc brakes, higher power; SC sunroof coupe is very desirable

1969-1973 911 -- long wheelbase, light, simple, fast, classic 911

1987-1989 911 -- G50 gearbox in bulletproof, rust-resistant 3.2L package

1995-1998 993 -- Last of the air-cooled, compact 911s; daily driveable

Some would add the 914-4 and 914-6, though it's hard to warm up to the looks.

From what I understand (Maybe Kds can elaborate), the later 964s had a lot of the bug fixes in, but build quality still wasn't great and frankly the cars look a little dated with the heavy plastic valances and Pep Boys-looking tail light treatment.

Like I said, though, I think you lose the classic car charm after 1973 and then you're into good value used cars -- nothing wrong with that, but it's a different game,