What's the proper way to split up payment for a date?

The inviting party pays unless Dutch is agreed upon beforehand.

I'd pick two or three unless he offers number one. 

I'm old-fashioned.  If a man asks me out on a date, I expect him to pick up the tab.  I don't expect him to take me to a very expensive restaurant - whatever is within his price range.  If the relationship gets serious, then I would offer to pay sometimes or pay for some portion, but for the most part, the man should be prepared to pay.

Man pays.