Dynamic IP friendly SPAs.
At last, Linksys just upgraded their SPA (formely Sipura) 942/962 series phone firmware. Among many other bugfixes, the new firmware fixes a number of longstanding and extremely annoying SIP registration bugs (CSCsm28353, CSCsk69012) that afflicted dynamic IP ADSL users whose external (routable) IP address gets changed frequently and necessitated a relatively long process to make the phone behave properly. Kudos to Linksys for fixing this, albeit quite late.