According to Amick, the Kings are at $62 million in committed salary next season after the Bibby trade, however, I'm pretty sure that includes Artest's deal (since he has an opt-out), so really they're around $54 million. The salary cap will probably be around $57 million, meaning if we clear Brad's salary for expirings (such as to Orlando) we could potentially have about $13 million in cap room THIS offseason.
In terms of fit, need and potential, I think this would be the list (keeping in mind that we could potentially sign two guys -- one bigger name and one smaller one). This isn't necessarily a rank of how good I think these players are, but rather ranked in order of how much they make sense for the Kings:
1) Jose Calderon - PG of the future. Steady, consistent, can push the ball and hit the outside shot. He's a restricted free agent and Toronto is probably going to want to re-sign him, but with TJ Ford already locked up in a big deal, how much can they pay these two guys to split time at PG?
2) Josh Smith - really more of a SF, but has shown he can play at PF in a running game. Great shotblocker and diversifying offensive game. Supposedly a head-case.
3) Elton Brand - a little older than the other guys on the list, and coming off bad ankle injury, but pre-injury was one of the best PFs in the league. Still only 28, but a lot of mileage.
4) Monta Ellis - we've seen what he can do. Some question about whether he could play the point, but I think he's shown flashes of PG ability and will grow into the role. Ellis/Martin would be a killer backcourt.
5) Luol Deng - maybe not the best fit since we're already jammed at SF, but a good hustle-player who doesn't need the ball
6) Beno - tough to know what his value would be around the league, and I'm not convinced he'd be a top-flight PG. But still young and a solid point guard.
7) Ben Gordon - tough player to place on the list, because he's a great 1/2 sparkplug off the bench, but probably not worth whatever money he's going to get in the offseason
8) Louis Williams - another 2 trapped in a point guard's body, but has shown he can score in bunches and is only 21.
9) Delonte West - forgotten man in Seattle, but was pretty solid in Boston
10) Kwame Brown - Just kidding.
Some people not on the list -- Biedrins, Okafor, Arenas, Iguodala, Marion, Jermaine O'Neal. The first four are likely to get re-signed by their own teams, and the last two probably won't opt out.