How much aeroplane do you really need?
there are a couple of threads running which I think are related to the subject of how much aeroplane one really needs, although they don't say that specifically. The threads are "Farmstrip Flying" and "Why do people give up?"
There is a lot of good flying to be experienced at the bargain basement end of the market. I know, I live there. I fly a two seat, 3 axis rag and tube microlight. It cruises at 65 to 70 mph, drinks about 14 litres of mogas an hour. It is just the job for bimbling about. With a little forethought it is OK for going further afield. It was cheap to buy, it is cheap to maintain and it is quite happy popping into and out of grass airstrips (read low landing fees). It doesn't need to go to licensed fields or use miles of tarmac.
At the end of August it took myself and er indoors down to Blois, in the Loire valley, for a long weekend. We travelled light, we travelled cheaply, we travelled slowly and we enjoyed the scenery. We got caught by the weather and stayed 2 days longer than intended but there was no pressure to get the aircraft back for the next hirer. Try that in your rented school aircraft.
From this viewpoint I look at many threads on this BB with some amusement. While there is nothing wrong with lusting after some of the hotships I can't help thinking that for many PPLs a move down market would be better. A reduction in the hourly cost might lead to an increase in the number of hours flown. Perhaps fewer pilots would give up and others would be more proficient, due to being more current. I find that the more flying I do, the more people I meet and the better the social side of flying becomes, leading to more invitations to go to flyins.......
You just need to escape from the flying school/licensed field/renting spam can environment. There is another world out there if you look for it.
I think that the answer to the title question is, you only need an aircraft as fast as the slowest aircraft in the group of people you fly with. If you can't afford to keep up, join a slower group.
It works for me.