Looks to me like you're getting a lot of good advice here.
Personally, I think the investment in a dynamo system is worth it -- I'm amazed at how good (i.e. bright) they've gotten in the past few years, and I love that it's always ready to go. Also, even with rechargeable batteries, I found myself frequently trying to conserve my batteries, and I'd resist using my lights unless absolutely necessary. With my dynamo system, however, I pretty much leave it on all of the time.
That said, the battery units like the Planet Bike Blaze are a good way to go as well, and they're much cheaper.
I don't think you can go too far wrong.