Hmmm... great discussion...
I have never owned an aeroplane, but I slept in a Holiday Inn Express last night, so I fee qualified to comment...
Ha Ha.
Actually, I'm just going to relay some thoughts that were given to me by friends who own aeroplanes.
1. If you've never owned an aeroplane before, start out easy, reduce your risk.
2. It never costs as little as the brochure says it will cost.
3. The plane is never as available as a rental (hire) plane will be. (this applies more to share schemes, but every so often the plane is in for minor repairs, inspections, etc., and when this happens at the "club", you can rent/hire a different aeroplane)
4. If you're flying less than about 200 hours per year, then being the sole owner of an aeroplane is an indulgence, and it will cost more per hour than you expect (double your expectations), because the engine will run out faster, it will require more maintenance work during the "off" season, etc.
My suggestion, based on what I've learned from others, is that with only 70 hours per year, and you want to have a "newer" plane, then find a club with newer planes for hire, and hire those instead. Or, if you have to be an owner, then get into a share scheme on a newer plane.
Of course, if you've got money to burn, then you could either send me some, so I can fly more, or you could buy a new plane and be prepared for down-time for the maintenance required due to flying it so little.
That said, I don't think fixing up an older 172 comes close to what a new one is like. Having hired newish 172's, I find them quieter, smoother, more comfortable, and cleaner, all of which lead to a more comfortable flight, and also help passengers to feel more comfortable (particularly on their first few flights).