I am going to tell you to go a different route. I think your choice needs to be a 912. here is why. the top 2 reasons to hate a 911 are
1. Rust and 2. Motor repairs. All three choices on your list suffer from problem number 1. Rust. 911 & 914 are the more difficult of the three to work on. If your budget is small like mine. You probably want to avoid the 911 shop for engine repairs they are high dollar. But you stated you had limited skills with the wrenches. So what happens? 911 gets neglected and you are mad about 911 motors. You need to have a 912 they are the easiest to work on by far(anyone with a book can learn). If for some reason you cant work on it a good VW wrench can (way cheaper than 911 wrenches). The 912 has all of the good looks of the 911 and will probably get you more thumbs up than a 911 or 914. And in closing I think that a Good 912 will be appreciating in value faster than a 914 or 911 74-89. That is how I see it.

linter - you'll find a good car if you look long enough, but make some new local friends - join PCA or something - hang out with Porsche gearheads and you'll pick up enough knowledge and have enough help with little things that will cut down on your maintenance costs.

And you'll have MORE fun!

JB

PS: peon77 is right - 912's are fun cars! I've never owned one, but have driven a few. The first Porsche I drove was a '66 912!