draccent,
I think you're doing all this in the wrong order.
Firstly, learn to fly. You will learn all about aircraft, and find out what type you like flying as opposed to the ones you just think you'll like flying. You'll learn about different types of aircraft. You'll meet people - hirers, owners, builders etc - and be able to ask them lots of questions.
Then decide what you want to spend your time actually doing. As has been said, building planes takes a long, long time, and is only really suitable for people who enjoy the building as much as the flying. Some people enjoy the building more (odd, I know!) and sell on the plane; you could get a good deal that way. There are also some good second hand deals around, once you know what it is you're looking for.
You mentioned you found an old C150. "Old" in an aircraft doesn't matter, so long as it's in good shape, and it probably won't be allowed to fly if it isn't...I'm on shaky ground here, as I don't know the rules for such things outside the UK.
You talk about range and the capability to go anywhere. What exactly do you mean? If you want an IFR tourer, that'll cost serious money. If you want to fly for a few hours and take photos, a C150 or somethng similar but possibly cheaper to insure and maintain will do just fine.
Unless you HAVE to gloat over it being all yours, why not buy a share? Far cheaper, and you don't have to worry about maintenance and insurance all by yourself.
Genghis' top tip is spot-on - learn to fly first...and do your research at the same time.