the docking station is only important if you are going to use it as a desktop machine as well with a second monitor, power, network adapter, printer, etc. If not, you can just have a USB DVD as you describe.
Vista is quite stable now and provides a lot better handwriting recognition. That being said, it is a bit of a pain to get used to and has some quirks - but what software doesn't. Make sure all the software you will use is Vista friendly.
Lenovo is shipping in 2-3 weeeks depending on the cofiguration. Not nearly as bad as when they released it.