Both would be fine, but I'd prefer Corporation over Evolution solely because they tried to replicate Evolution (in some ways) with Legacy and I just wasn't a big fan of that stable. Plus, if they went with the Corporation angle, it would directly, and inevitably lead to a feud with Punk somewhere down the line, which is another thing I want to see.
We could all be wrong and they could just milk the whole thing for a week or two with no actual answers.
Wait... Could Orton take out Cena, punt him in the head to write him off TV?
I mean it works.