+1 on MSFS 10 (FSX). I got the CH Products Yoke and this software about a month ago and have tore it up. You can grab your approach plates and put a 172 (or any other airplane) at the airport of your choice and fly the approaches there. It works.
Also, there is some add-on stuff out there that are for pilots to really use MSFS as a sim. I downloaded some approaches from:
http://www.bruceair.com/more_flights/more_practice_flights.htm
DME Arc, ILS, DP, and some other nice IFR work.
The Mooney has a GNS 530 in it and you can use that to fly GPS approaches. Looks and works like the real thing. Although, it does not have DPs (SIDs) with it, nor can you build an actual flight plan to fly like you can with the real GNS 430 or 530.
The only complaint that I have with FSX is the turn coordinator. The ball always stays in the center. However, the purpose that I use FSX is to practice procedures and trying to keep a proficient scan going while running through text book procedures when shooting an approach. The 172SP in FSX is actually good. I used it to learn how to muck around with the autopilot and it is no different than the real thing. I think it is even better than most of the nice sims that are at some of the flight schools.
Good luck, and hope this input helps!