I personally thing we could go either way. I like the idea of a field general, ball hawking FS, and Landry certaintly fits that bill, but I also think Shulters can be a contibuter on a playoff team, so the need isn't quite as big.
I do know are safeties are seting team records for sacks and all this year, but I think a play like Bing would make our saftey blitz's so much more effective. Bell has made some big plays this year, but how many times have you seen the SS creep up and blitz and just get tossed aside, exposing our secondary. A player like Bing could increase the chances that our blitz gets into the QB's face, boosting our secondarys chances of making a big play.
I see our attacking style of defense very similar to the Steelers. It is just awesome watching Polemalu come up to the line and take a good angle at the QB and smacking him in the face. I think we need a star in that position to duplicate their success and Bing just fits that profile for me. I wouldn't be upset at all with Landry or Huff, but my preference for big fast safeties is fully satisfied in a guy like Bing.