A tip, i just discovered this - When you use a patcher like the one that enables 32x32 textures (i think its called HD Patcher), then it patches minecraft back to 1.2.2 but won't update when you start it again.

There is a version file in the directory where the minecraft.jar is, maybe it is easy to change it to 1.2.3 too and keep the old client if you still have? I haven't opened it yet.