I had to go with GSP over Silva. GSP is my favorite fighter dating back 6 yrs now.
Unfortunately we will probably never see either match. Silva vs GSP would have made since a few years ago. It's always hard going against the Spider (Best fighter ever until proven otherwise) but GSP is a very smart fighter and will take Silva down with his superior wrestling and do some GnP. I don't think he would ever be able to finish him though.
The match that I want to see within the next year or 2 after Bones finishes the rest of the LHW division is JDS vs. Bones. Jones could fight at his natural weight (HW) and this match would be epic. I'm also a huge JDS fan and that matchup could eventually happen as long as both fighters continue to win. Figure Jones still has Hendo, Machida, Gustafsson, maybe Phil Davis and maybe Glover. And JDS has Cain, Reem, maybe Cormier. Like I said if they both can win all their matches this fight needs to happen. I don't think anyone would disagree IMO.