Locked telephones have set a bad precedent and some broadband ISPs are attempting to do the same thing with routers. In the UK, Sky, part of NewsCorp, supplies a badged NetGear DG834G or suchlike with patched firmware. However, it isn't obvious how to change the settings - or change the account details to make it work with other ADSL ISPs. It doesn't have default NetGear username/password of admin/password and uses admin/sky instead. Thankfully, the GPL2 source is available. However, I'm very concerned that in the future ISPs could offer enhanced or exclusive access through routers which are not trivial lock down or patch and which would be incompatible with other ISPs.
