...ignoring the fact that the female leads almost always end up dying some horrible, painful death of course ^_^
I'd want to be either Lisa - despite the fact that I don't like her at all, she did get to live with Dean for a year - or Sarah because she got to go on a date with Sam while he was still remotely innocent and "Sammy"-like.
I want to live in Eureka! A town of lovable geniuses on the cutting edge of science... what's not to love?!
As for what character I'd be? None of them really fit where I want to be in life so can't I just join their world as me? =P If I had to pick it would be Allison Blake because she has the love of a great man, a wonderful son and clearance that gets her into wherever she wants! And everything always works out in the end. :)