I also enjoy playing with just one club on an occassional after dinner visit to the course. But to still feel like I am getting the full feel of the course, I want a driver (on some older shorter courses the driver can be left out and the 3 wood can be used), a putter and a sand wedge. From there I add a fairway wood, and a few irons. I think 6 clubs is the low end for me. With 6 clubs I would go: driver, putter, SW, 5wood, 5iron, 8iron. I have played a lot of golf with only 7 clubs (I like having both a PW & a SW in my bag).
I prefer to try to never play with more than 10 clubs, and I think that should be the limit in the rules.
To answer a prior post about why one prefers to play with less clubs, I prefer less clubs for the additonal challange of having to play a variety of shots. Rather than picking the club that matches the yardage and then making the same swing all day, I enjoy having to play an "easy 5 iron" for 150 yards, or having to decide where to try to run a shot onto a green.
There are other benefits to having less clubs. Less clubs makes buying equipment less expensive. Less clubs, makes the bag lighter, thus easier to walk, thus again making the game less expensive. Also, more walking means more health benefits from playing golf.