Here's a list of 2012 impact FAs by position (link to a full list is also available):
Ranking The 2012 NBA Free Agents | HOOPSWORLD | Basketball News & NBA Rumors
The list is a bit outdated (Howard and Chandler are still listed, for instance).
Deron Williams is, by far, the most attractive target at any position. Gordon and Batum top their positions, while the list of power players makes me happy we appear to be quite stocked there (either old or won't be let go by their current teams).
Looking at our roster as constructed today, adding JV and a high pick which is NOT going to be a point guard, the only player who makes absolute sense for BC to go after is Deron. Yes, the chances are slim, but the rewards of having an elite PG added to the existing talent pool are too huge to ignore.
Frankly, noone else on the list excites me compared to what we have today.