Giving the online retailers a day to get their shops updated it seems like the new Polycom SoundPoint IP450 is going to start out selling for around $220. Given that the IP550 is listed in places for only a little more ($230) I suspect that the actual selling price of the IP450 will eventually drop to around $190-200.
Update: I was reminded that there are versions with and without the power supplies, which is typically about a $20 difference in price. Since the phone supports standard POE many will not want the power supply.
Update II: I just purchased four of these handsets for a new office. I paid $189 without the power supplies, which is $40 more than the IP430s that we had originally thougt to use. With these IP450s, my IP650s and a new IP6000 conference phone my employer will be poised to start seeing the benefits of wideband telephony.