HTC's history is littered with phones that are great ideas before their time. Or more likely great ideas held back by the Windows Mobile platform they ran on.
Some of those ideas have become embedded in the smartphone experience, whilst others have been forgotten.
One such phone was the HTC Advantage.
First 5" screen on a phone? Check. Mass Storage? Yes. Auto rotate? Video out? USB host? Gesture controls? Yes, all of those were in there too.
It was a huge phone, even by the standard of the day. But aside from its size it would stand comparison with modern phones for its feature set.
One thing that HTC added that no one else has copied yet is the detachable keyboard. A slim, magnetic qwerty keyboard that turned it into a mini laptop when attached magnetically, and acted as a screen cover when not in use, again by virtue of magnetism.
I can think of a few of today's smartphones that could benefit from a similar arrangement...