This is the wrong forum to open such a thread, and besides, i fail to see the use for it... I don't really think the characters can be compared.
Anyway, i'll move this to the Lisa's Family board if anyone wants to say something about it.

I don't know how you can compare Lisa to Meg since the second one doesn't have any personality at all...
I never saw her being nice, never saw her being angry, never saw her acting weird or smart... she acts like a secondary character in Family Guy, even Brian, heck, even that sex-obsessed neighbor (forgot the name) has a miles more developed character!

That would be Quagmire! I actually know someone who sort of looks and acts like him lol.

About Lisa vs Meg.... its not a question i think that can be answered. They are both totally different types of characters. One is young one is a teenager. They play different roles in thier respective families. And as Serge said, Mwg is used as a plot device most of the time rather than a member of the family.

Someone posted similar sort of thread way back about Gwen Tennyson (Ben 10) & Lisa, which was made more sense, as they near enough in age, have same personalities, same situations and both are central to the respected series. With some explanations of why thread was posted and some details of the characters too. This is more the kind of thing we can discuss here.

-> http://www.lisa-simpson.net/topic/471.msg10458#msg10458