Unless you will have 2.5" plumbing or larger, a 1.5hp pump will be too large for your system. You will also need a filter that can handle the flow of a pump that large. If you are going to use a 2-speed pump (highly recommended), the occasional use of the high speed of a 1.5hp would probably not cause many problems, even on 2" plumbing.

I have successfully filtered older pools in the 40 - 50k gallon range that had very undersize (for today's standards) plumbing, hand-formed skimmers and usually only 1 return line and inlet with 1/2 and 3/4hp pumps. Bigger is seldom better in pool pump sizing.