Ha! dubbleyew eight I recognise that! It goes with any big purchase.
Don't rent to a club/school. It is the worst of both worlds. The aircraft is booked when you want it and on the other hand you will be concerned about talking it away when it could be earning money. Some renters are incredibly thick when it comes to looking after an aircraft.
I understand your feelings about a group however it really is a good compromise. All the groups I have been involved with had a principal who was the origional purchaser and shares were then sold. The principal still had the last say.
Pick a common type to prevent months of down time and surprise expense. The Cessna SID is less of an issue now as in most countries it is not compulsory. It is however a great bargaining tool.
The other guys here have offered some good advice. I agree with A and C and Adam that you should look ahead as you can outgrow an aeroplane very quickly.
Finally, you mentioned that you were not concerned with speed. Please do consider this if you intend to go anywhere. A 90 knot aeroplane may sound OK. Remember a 20 knot wind on the surface will be much stronger at altitude and may prevent you from getting home the same day.
D.O.