I've played with groups as small as one (one-on-one gaming can have its advantages; if the PC is a Conan type, it's really the only way!) and as large as ten. Is there an optimal number? I guess is really depends on the PCs, the needs of the characters and the story.

When I was in high school (far too long ago) there was a period of six months in which only one other friend and I gamed. At first, we tried to fill the empty spaces with multiple characters, but that usually meant that one character had a personality and the others became arsenals. And, when push came to shove, there was always an expendable character.

Then we decided to have one PC and one NPC. It worked out really well. If the PC every got really stumped, or was focused too much on the red herring, the NPC could always nudge him back onto the track. If the PC was bashing his head against the wall, the NPC could make certain suggestions. The PC was the star of the show, but the NPC had a very strong personality. For one-on-one, it turned out to be quite a lot of fun. Anyway, in a lot of good, swashbuckling fiction, there is one main character--the focus of the tale. Three Musketeers is really about one guy: d'Artagnan.

There is an entirely different level of fun when you play with a huge group. I personally think that ten is too many, but the DM did a credible job of controlling everything and allowing most of us our moment in the sun. There were, however, two players that got severely left behind. They became no more than the walking arsenals I mentioned above, yet there were two people behind them who had hoped for a bit of fun. Those two never complained, but they weren't the types that would. I guess a poor game is better than no game at all, but everyone really should have a chance to shine.

And this begs the question: when do you reach the limit?

While I can't answer for everyone out there, I can answer for me. I figure about six is the perfect number. If you have a diverse group--a couple of fighters, a mage, a thief, maybe a cleric and what-have-you--six works out well. Everyone has their moment in the sun. There will usually be a leader type, and even the quietest of players, especially among good players, will get pushed onto the stage. Now this isn't to say that seven is too many or five too few. We aren't talking about the Holy Hand-Grenade of Antioch here. Depending on the players, and the strength of their egos, four might be too many and ten might be too few. On average, though, I'd say six is about right.

The group I play in right now has four players and a DM. It works out pretty well. We've got two fighters, a thief and me, the bard. No wizard and no cleric, but it's a low magic world. If we had two other players, in this particular mix, I think they'd be drowned in egos. That's just the chemistry of this group, and it's the exception that proves the rule.

In the end, it depends on the DM and the players as to the perfect group size. Sometimes one DM and one player, with good characters, can be a heck of a lot of fun. Sometimes ten players, if they are considerate and diverse, can create an epic level and exciting adventure. For my money, though, somewhere in the middle, and I've arbitrarily said six, is just about perfect.

And since one always must qualify one's remarks, I'll leave off with a "your mileage may vary."