This got me thinking: I can count the times I've used my Pre in landscape mode on one hand. And most of those times happened only because I was just playing around, not really using the phone/trying to do anything.
So...why don't I use the Pre in landscape mode more often?
Aside from the fact that you have to hack to get email to re-orient in landscape mode, the main reason I don't use the phone that way more often (at all, really) is that the only way to interact with the phone in landscape mode is really to tap the screen or turn up the volume. If you are doing anything that requires more than just watching video, viewing images, or following links (any web-based searching or form filling, for example), it is simply impractical to use landscape orientation.
I do really like having a hard keyboard that doesn't eat up valuable screen real estate, but a soft keyboard for text entry in landscape mode sure would make the phone a lot better for interacting with web pages. And for a phone that distinguishes itself as a dynamic, multi-tasking web and communications platform (as opposed to, say, the iPhone which distinguishes itself as a media and applications launcher), the absence of this landscape mode functionality is a pretty big loss.
I'm not sure how far in the future Palm plans to bring this feature to the phone (if at all), but I'm fairly certain it would make a lot of users very happy if they brought it sooner rather than later.