We have a fiberglass inground pool that was installed in Aug '01. It's 14 x 28 with a slide, 4 color light, cascade (like a little waterfall), upgraded finish (speckled blue), 2 inlaid tile dolphins on the bottom of the deep end, dolphin tiles around the top edge, extra concrete to have a bigger pool deck and a "coped" concrete edge was just over 30K. Code in our area is to have a "BOCA" code fence either around the pool or around the yard. We fenced just the pool for an additional 3K. Landscaping and lawn repair was almost another 4K. So all told it was just shy of 40K. We could have done it for less (white light, no slide, smaller pool deck, flat concrete edge, plain finish, no tile edge or dolphins, no cascade, no landscaping) and probably would have saved 10K. But we love it and it is a beautiful little pool. Concrete or vinyl liners run about the same amount of $, a lot of the cost is the excavation and the dumping costs. But vinyl liners eventually need to be replaced (drain the pool, cost, etc) and the concrete (gunite) can need repairs down the road as well (again, drain the pool, cost, down time, etc). One poster said they didn't add to their insurance b/c they were covered and that is technically true. But we did add a 1M umbrella policy to our coverage for less than $150/year for peace of mind. If someone sues you because little Susie or Jimmy got hurt at your pool, most homeowners policies limits are not high enough to pay out on a judgement against you. And legally pools are considered an "attractive nusiance" by most town/cities/counties.
You also want to think about the increased utility costs (gas and electric for heating the pool and running the filter system), opening and closing costs each year, chemical costs, yadda, yadda, yadda.
It sounds like a lot, but it sounds more intense than it really is, at least now that we have the pool!