(Specifically Workstation - i.e. the Gnome variant, but I've used other spins and they're also great)
Pretty up to date, reliable, spearheads new developments that go on to benefit the Linux desktop as a whole, they don't make a bunch of crazy alterations to the DEs they ship.
And to think I was reluctant to try it for ages because the name sounds like it'd be some neckbeardy distro.