What's your ideal MMO group size?

Massively's commenters got me thinking on MMO group size after an article a few weeks ago about socially soloing in games. Even though I like and support the option to solo in MMOs, my favorite games have actually had very large group sizes, far larger than the now-standard World of Warcraft five. Some newer games cut that down to four! But I really loved classic Star Wars Galaxies' 20-person groups and even City of Heroes' and Guild Wars 1's eight-member parties. Something about throwing a huge swarm of people into a group and going out and just Doing Something really appealed to me in a "the more, the merrier" way, especially when the game scaled to meet our needs rather than tried to mash us into a mold for prefab content. And nothing seems worse than having six guildies online and being forced to leave one behind because parties cap at five bodies.

What do you think -- what's your ideal MMO group size?

TH

I've always been used to the number five, Gw2, Swtor, WoW. So i don't see it not able to work.