The wonderful thing is that this doesn't turn into the typical two men fighting over the woman (thank you) instead it's two very different men and their views and opinions on life.
I have to admit that whenI first saw this I really didn't like it, it was just another awful American sitcom, but the more I see of it, the more I find myself really enjoying it.
Leonard is sweet in a naive sort of way, he doesn't quite get what's going on and he doesn't know how to react, Penny is the typical ditzy blonde with moments of complete clarity, and Sheldon, what can yoy say about Sheldon, neurotic in the extreme, but very funny to watch. We also have their friends Howard and Raj, also geeks, although Howard thinks that he's a womaniser.
Personally I have a real fondness for Raj, who barely speaks in Penny's presence for the first series because she makes him nervous.
It's good because it's original, because they haven't gone down the usual predictable route, and because the performances are good across the board, there isn't anyone who gives a bad performace. Basically, it's a feel good, entertaining programme that'll make you giggle.