I'm definitely with Gwen but like in Harry Potter and the Half-Blood Prince when Ginny was dating Dean Thomas, I wouldn't mind Parker dating Liz until eventually realising that he'd really be better off with Gwen, which would happen by Movie 1's end. Having Gwen die in Movie 3 would be the ideal thing to do as I'm also hoping that they include Doc Ock killing off her father in possibly Movie 2.
I'd like Betty in there too somehow but would prefer it to be a passing mention that they dated once he gets a job at the Bugle.