I've done some research on the pool issue. As far as in-ground goes you've got three choices: gunite (commonly referred to as concrete), liner pools and fiberglass.
Gunite pools are the high end of things. They're typically custom, which means diving board(s) and slides wherever you want them, depth to whatever, waterfalls, wading area, you name it they can pretty much do it. But be prepared, these are the most expensive by a long shot. Maintenance on them isn’t too bad, but expect to resurface it in about fifteen years depending upon how well you maintain it. Typically the algae issues seem to take their toll a bit harder on the gunite pools because of their pourous nature or the fact that there are natural tile borders with grout that need to be scrubed clean at the start of the season. All in all though, no more maintenance than you’ll find with the other pools.
Liner pools, are a step below the gunite pools. The design, shape and other aspects of the pool won’t be a flexible as the gunite, but then again, the liner pool is cheaper. Maintenance; expect the same, but I’ve seen liners pull free from the edge and drop into the water allowing water to get between the liner and the structure. This is a big problem when this happens. The life of a liner depends on how well you take care of the pool. My in-laws have a liner pool and they got about twenty years out of the first liner before having it replaced.
Fiberglass seems to be the way to go as far as I’m concerned. You can get them large enough to dive into if that’s your thing. Shapes and sizes vary enough to the point where you should be able to find one that suits you. Best of all they come on a trailer and they’re dropped in the hole and ready for swimming in as little as two days. Also, if you have some plumbing experience, excavation experience and patience, you can do the install yourself; saving about 50%. I’ve priced them out and you can get a reasonable pool shell for anywhere between $7 to $15k. Add in the filtration system, cover and deck and you should be in under $20k (doing it yourself).