I'm in the same boat and posted a similar question.
The Blackberry certainly is the "business like" choice, but really it seems that what it does best is email. I've noticed that people are very loyal to it that have been users, but I've heard many say that if email isn't by far your priority, then it's not always the absolute clear choice. I for one won't be getting one, I don't find something like the Pearl functional for either writing with the tiny keys sharing multiple letters or the small screen for browsing. The Curve looks like a nice device, but the reality seems to me that it's just a more functional, sleeker version of the standard Blackberry form factor--namely a rectangle block with crowded keys on the bottom and a screen on top. It's just another tweaked version of the exact same phone that bankers and lawyers started carrying 5 years now. It's just an evolution of the same old thing.
I think like you, I find the design of the Sidekick appealing, just seems more functional for writing and browsing, but totally agree that the image of it is for teens.
This device I am seriously considering, it runs over the Sprint network came out last week, and the reviews have been excellent. It's like the Sidekick in some ways. Unfortunately, this may bother you, it's marketed at the myspace crowd as well. Still, probably worth a look. The device is pretty new, unique and functional and the offered plans can't be beat for data IMO:
http://www.helio.com/#devices_ocean
My other thought reading your requirements and not caring about price is the iPhone. I know it has its issues and detractors, but if you want a cool phone that will give you the basic functionality and very cool, unique web browsing, it might be worth a look for you. Look at the link below and view the demonstration on web browsing, it looks like it will be great for that with the touchscreen and the screen size. You're not going to get that in anything else. I need to have something in place for a trip before it will be available in a month, and the cost is a turnoff for me at this stage, but if that's not an issue for you, you should really think about it. You'll get the "wow" factor without it being a toy like the Sidekick:
http://www.apple.com/iphone/
In fact, if I'm interpreting your priorities correctly, web browsing, this might be the way to go for you.
Plenty of others here are far better resources than me on this question (I don't even have one of these phones yet LOL), but I have been looking and researching a while, and it sounds like we value some of the same things so I thought I'd throw in my 2 cents. Good luck.
