You point out a lot of why I didn't get so much of the bickering over the early upgrade problems for iPhone 3G buyers. It really isn't worth it to buy a new iPhone every year unless you can almost make your money back on eBay by selling the old one.
As you (or someone else) said, it's definitely worth it if you had the original model. I can't just sync up my entire music library, but I can just click on every playlist I have created (many different artist playlists), put 1,000 photos on there, put an entire season of a TV show, throw in a couple of movies, actually use music videos -- in other words, it was worth it for me. The 32GB is the biggest deal, and the zippy speed (both hardware and from EDGE to 3G) is right behind. Jury is still out on the camera, but it seems to be noticeably better, and the video looks pretty good playing back on my phone.