How many modifications are best to install?

[cheat-master30]

In the past, I have seen quite a few people get told they add far too much to their boards (I won't name anyone, but I mean like that member who said they have 200 + modifications). So how many would people here say is the best amount to have?

For me, it comes to this:

I add either if the members would really like it (shop, gallery, points system, arcade, interactive profiles, shoutbox) or whether it would be helpful (posts not being bumped, banning users from topics). Only thing is that I seem to have a lot of the second type that get a bit of praise, then just about forgotten about.

So how many would you consider is the right number?