Plus, next years free agent class is pretty strong(a lot stronger than this year IIRC).
Here's an ESPN insider column about it.
It's basically loaded, so even if a lot of players don't change teams, they're going to use up a lot of money to sign their big guys, and the teams with a lot of money will probably give some above average player a Rashard Lewis contract, thus killing their cap space.
Here's just a sample though:
Duncan, Garnett, Brand, Arenas, Marion, J O'Neal, Iverson, Baron Davis, Magette, Artest, Lafrentz, Juwan Howard, Kenny Thomas, Marbury, Steve Francis, Stromile Swift, Rasho, Keith Bogans, Trevor Ariza, Monta Ellis, Jose Calderon, Craig Smith, Walter Hermann, Ronny Turiaf, Daniel Gibson, Gomes, Oberto, Salim Stoudamire, Hassan Adams, Tony Allen, JR Smith, Robert Swift, Carlos Delfino, Randolph Morris, Telfair, Antawn Jamison(unrestricted), Ricky Davis(UR), Antonio Mcdyess(UR), Mourning(UR), Diop(UR), Bowen(UR), Kwame Brown(UR), Jason Williams(UR), Sam Cassel(UR), Chris Duhon(UR), Michael Finley(UR), Brent Barry(UR), Kurt Thomas(UR), Nachbar(UR), Arroyo, Horry, Gricek, Dooling, Najera, Juan Dixon(I'd love to see him on the Cavs), Mo Evens, Primo Brezec(he would be a great back up Center), and plenty of other quality players are all unrestricted free agents.
Basically, it's going to be very hard for Sasha and Andy to get what they're asking for next year.
I'm not sure which teams will have a lot of money next year(I think Atlanta, Charlotte, and Chicago still, though Chicago will have to spend a lot of money on Deng, Hinrich, et al eventually, so I'm not sure how much they're be able to spend).