To the left of the trackball you'll find a call button and a home button, both of which are self explanatory. To the right of the trackball there's a hangup/power button and a back button, again pretty standard stuff. Lastly, there's a Menu button above the trackball, which again works in a similar manner to a BlackBerry. The options brought up by the Menu button depend on what application or screen you have open at the time. This will probably be the most pressed button on the G1, and given the open source nature of Android, I'm sure we'll be seeing a host of cool little options attached to it in the coming months.
On the right edge is a shortcut button for the 3-megapixel camera, while the left edge is home to the volume controls. Along the bottom edge is a flap that hides a mini-USB port, which also happens to be the only socket of any kind on the phone. Yes, that's right, a phone that is supposed to be the ultimate mobile Internet and multimedia device doesn't have a 3.5mm headphone jack - words just fail me! Why HTC seem to think it's acceptable that a handset with such lofty media aspirations doesn't need a headphone socket is beyond me. Even RIM has seen the light and equipped the BlackBerry Bold with a 3.5mm socket for Heaven's sake.
Adding insult to injury, the bundled headset is a single piece affair, so you can't even plug a decent set of headphones into that. At the very least, T-Mobile should be bundling a mini-USB to 3.5mm headphone socket adapter in the box, but such an accessory is woefully conspicuous by its absence. To make matters worse, the G1 sports an impressive array of codec support for a phone - MP3, AAC, WMA and even OGG Vorbis - so being limited to the awful bundled headset is even more of a disappointment.
In true HTC style, there's a full, hardware QWERTY keyboard hiding inside the G1, but the way in which the keyboard is revealed is very different from most other handsets. Obviously the keyboard is hiding behind the screen, but instead of the screen sliding straight up and out of the way, it actually slides out, then back in again in a manner that's hard to describe. What I will say is that the way the screen slides is probably the best design aspect of the whole phone, and I've yet to hand the G1 to anyone without them commenting on the hinge mechanism.
The keyboard takes a bit of getting used to, and much of the learning experience has nothing to do with the keyboard itself. The most difficult thing to get to grips with is that curved lip at the bottom of the G1, which, of course, doesn't slide out of the way, and stays in situ with the device in its landscape mode. The problem with the curved lip is that you have to reach your thumb over it to get to the keyboard, which isn't something that comes naturally.
It's a shame that the G1 enforces this contortionist typing style, because the keyboard itself is pretty good. Despite the keys being quite small, and literally flush with the surface, they have a decent amount of travel and feel to them. In fact I'd go as far as saying that the keyboard on the G1 is one of the better examples I've used. After a bit of practice I even managed to make my right thumb equally as productive as my left, despite having to navigate over that curved lip for every press. That said, I did find that my right thumb started to ache long before my left. And it also has to be said that the virtual keyboard on the iPhone still blows the G1's text input method away.