I would like to see Tom Welling as Superman and I would love for the movie to be a continuation of Smallville. Yes, it's not the best show out there, the writing is often questionable and you can really see the limited budget, but those are problems that could easilly be solved by the jump to the big screen.
Of course the movie has to work on its own, so I would only reuse a few actors from the show, Tom Welling, Erica Durance, Michael McKean and Annette O'Toole. Everyone else has to go, Allison Mack and Cassidy Freeman could appear in minor roles (depending on what happens to Chloe and Tess in season 10, I'm not sure they're going to survive), but I don't want Lex, Lana, Kara etc. anywhere near the movie and as much as I like Oliver, there's no place for a second, more experienced superhero in a Superman movie, maybe in a second part, but not in the first.