HTC doesn't want to let Samsung one-up them at all, so they are fighting hard to be at least as good as Samsung in all areas. That's why we've seen the best processors on the market in the latest One X flagship, and also the best display on the market, which is currently the Super LCD 2, an IPS type panel.
One specific success story from Samsung that nobody thought would work, is the 5.3" Galaxy Note device with its best-in-class active digitizer stylus made by Wacom, that took a lot of people by surprise with how useful and lovely it actually is after you use it for a while, and you get rid of the feeling that it's too big compared to your older phone. Once you get used to it, it gets very hard to turn back to a smaller sized screen.
HTC understands this, so they are planning to also offer a similar sized device, at 5" (nice round number, isn't it?) with a smaller version of the stylus they used for the Flyer tablet. But the more interesting thing about this device is that it should have a 1080p resolution, putting it at a whooping 440 PPI. We still don't know if that extra resolution will make a difference in a positive way compared to a 720p resolution that we see in a high-end devices right now.
That kind of resolution should require a larger battery (not HTC's strong suit in general) and a more powerful GPU, so more resources will be expended to power this resolution. It remains to be seen if the impact of such a resolution is worth it. It is possible that once you see it compared to a 720p screen, the difference will be obvious, and the font will look much crisper on a 1080p screen. All things considered, I'd still be very curious to see such a resolution on a small screen before I make up my mind.