We are now playing with all the expansions in play (above ground) except for the Necromancer Island, so that makes for a dizzying array of race and power combinations and with the zany event cards there is so much replayability as well as strategic complexity. As always BoardGameGeek has all the info you could ever want on the game and a slew of other reviews and images.
We have played games with from 2 to 6 players and the game works very well, even with the extra person (just added to the 5 player board, no special rules used). I adore all the table-talk as people try to think through who is winning, who might be going to win and who needs to be controlled, all while trying to collect points for yourself - very social the way we play.
[Small World promo pic from the Days of Wonder site]
Even though the box might say the game takes 80 mins, I think all of our games have been over 120 or 150 minutes - but lotsa fun minutes in there. Even though the game is all cardboard, the artwork is full of character and creates all manner of 'roleplaying' opportunities around the table. I love the surprises as some strange race combo under an odd circumstance way out-performs our expectations.
I am glad there are the little storage pockets for the zillions of counters, saves us on the setup and packup time.
All up, Small World is a wonderful game, esp with more players - the friendlier the group the more fun as the social elements come into the playing of the game.