DanM - Don't feel disheartened that this hasn't been replied to. It's just that this has been brought up plenty of times before.
CTP had 32 civs, and that's a pretty nice number. There are always going to be people who want extras though, so being able to customise the civs is of high import.
How many civs you have playing at once is largely a question of how many resources you want the game to chew through, and how it will affect AI. Hopefully people with high-end PCs (unlike myself) will have the option to play with many civs at a time.