If Android's semi yearly updates aren't enough to keep your device completely fresh then Canonical has just what you need. They will be releasing Ubuntu for phones starting with the Galaxy Nexus in late February! This will probably release for HSPA+ devices only since Sprint and Verizon's proprietary code can often cause issues, but the source code will be released publicly so there is no limit to what the development community will be able to do with it. We should see versions for LTE soon after it releases. The OS will be distributed in an unfinished state so there may be a few bugs at first like with all software releases. Basic phone functionality should work at release!