It really is a fun, elegant, and yes, sturdy device. I've dropped mine twice so far (yeah, I felt like an idiot both times) but you would be hard pressed to find where it impacted. I have a protective cover over the screen and have had no problems with scratching whatsoever. Is it worth it? Depends. IMO Google Maps is worth the price of the entire phone. Checking traffic before hitting the freeways is priceless. The camera is decent, text messaging is more fun and usable (although you can't send images via messaging).
Watching podcasts or movies is also an amazing experience, the screen resolution is insane. I converted the movie 300 for my iPhone using Handbrake and everyone who sees it is blown away by how gorgeous it looks.
The down sides: AT&T is truly a company who doesn't care about customer service. They can't train employees fast enough to keep up with their burnout rate in customer support, so you're always talking to a noob who doesn't know squat about their plans, the phones, etc. It's frustrating and I would say the number 1 negative about owning an iPhone. The Edge network is the #2 negative of owning an iPhone. If you aren't on wifi then don't bother checking your email, loading web pages, etc. It's like being on a 9800 baud modem in a lightning storm.
I love my iPhone and would recommend it even with the negatives. If you never have to deal with AT&T then I think the plans are reasonable and you wouldn't have much to complain about other than the Edge network.