I think they stay put but who they pick is tough to figure out. They don't necessarily need a starter anywhere so they can draft for depth. They haven't spoken publicly much but KOC said he liked Brandel next to Darrisaw, suggesting that LG isn't a priority. Of course, that could just be spin and the Vikes are hoping Booker falls to them (he's the guard I want). The national media has us taking someone in the secondary - usually a safety but occasionally a corner - but I think the Vikings are actually confident with what they have right now. Jackson has been in the system for a few years and will take a bigger role, Blackmon is back, they added some nice pieces in FA (and might add Samuel). Unless someone like CB Will Johnson falls, I don't think they'll go there.
I think the Vikings are going to take a DL who can play the nose or play inside over the guard but they likely feel pretty confident about the edge and OLB on the roster. They want guys who can collapse the pocket. The draft is full of these guys but most might be gone by 97.
So my guess is that at 24 they try to trade back but don't find any good deals so then pick one of (in my order of preference) DL Grant, DL Harmon, LG Booker, LG Jackson.
I do think the Vikings might very well package 97 and a future pick to move up to get someone though.