A couple of points, from the tech specs page at:
http://www.apple.com/ipad/specs:
1. It DOES have a 3.5mm audio jack.
2. It has a dock connector. It will charge via USB. It will connect to cameras (with an adapter) and read (and I presume write) SD cards (with an adapter). I assume, then, it DOES have USB and could sync via USB, though this is not explicitly stated anywhere. So, you should be able to expand storage significantly with an SD card, but that big, ugly dongle... Would have been nice to have had a built-in SD slot.
No OS 4.0 announcement, I assume they are backed-up on the software development. 3.2 SDK available today with simulator to get developers going. I assume this is a stop-gap. Software just takes time, they've no magic for the software development process. Except for the lack of GPS and camera, it has the goods, the feature set will be built-out over time.
I'm sure it took an enormous effort for Apple to have the SDK available today, with all the support (samples, great documentation) that is typical of Apple. I'll be checking it out within the next few days, but of course won't be able to say anything about it here.
A bit of a disappointment that the chip is apparently not dual-core.