I have an HTC TouchPro II, mainly because I like the tilting screen and full keyboard. It qualifies on all of the categories you mentioned, as well. The onscreen SIP keyboard is much improved over earlier models, to the point that I use the pullout keyboard far less than I did on my previous phone. Still, even though it is no longer absolutely necessary, I like the slide out board for texting, as it's faster and more accurate.
It also has an ultrafast GPS receiver, a high capacity battery, an acceleration sensor, a light sensor built into the display that automatically adjusts the brightness, and about a hundred other minor features that make it pretty much a joy to use.
On the minus side, the processor is good, but would be better if they'd used a Snapdragon. I also have a minor ongoing problem with MS Voice Command announcements routing properly through bluetooth, but that's the only problem I have with it, which is saying a lot about such an ultra-sophisticated device. I could probably fix the one problem just by upgrading my headset to a more current device than the Jabra 8010 I'm using now. I had the Tilt (Titan II) before it, which was far buggier.
EDIT: Go with the HD2. Awesome specs. It has the Snapdragon, an upgraded 5 megapixel camera, and the excellent addition of a 3.5mm jack, which got left out of a lot of the TP2 versions. It's got a capacitive touch-grid. Big upgrade over the TP2! It's also got a built-in digital compass. Not a necessity, but nice, anyway. You lose the slide out keyboard, but having one is a matter of personal taste. In return, you get a phone with a slimmer profile, though I actually like the thicker, heftier feel of the TP2 over the more iPhone-like models.
The Corby is an OK phone, and you can always count on Samsung to make a solid product. In my job, I drivetest cell systems and we use Samsung products pretty frequently as test units. They're sturdy, high quality and well-designed. That said, the Corby is a nice phone, but lacking in 3G capability, GPS, Wi-Fi and a lot of other features I consider essential. It has a lot of MINOR features that are fun and handy, but, to a large degree, the more important core features are absent. It's a good phone if your network usage expectations are not too demanding.
In short, the HTC HD2 gives me a woody, and the Samsung Corby does not.
I might use the Corby as a "theme-park" phone. I sometimes visit theme-parks with water rides and stuff. On theme-park days, I like to put my SIM in my old Moto V557, because I don't care if it gets fried on a water ride. I'd feel about the same way about the Corby.