I've tried quite a few pipes, but the Screen Queen is the one I come back to: it has a good sized bowl (that doesn't need screens!), a great draw, and a surprisingly cool smoke with lots of flavour - but the thing that sets it apart is the niftiness of the way it all unscrews into its constituent parts, and just how easy that makes it to clean - which makes for a hassle-free, fresh and flavoursome smoke every time.
The only thing that would make it 5*+ for me would be if they added a screwable lid/wind-protector - and made a longer, version.