I don't think some people here understand that this isn't aimed at people who want to store and or backup photos of their cats. This is for people who need massive storage and need it quickly.
Every single thunderbolt product discussion on macrumors consists of people complaining about the absurd price premium, and other people saying that those people don't understand.
i think the truth is that there is no reason to have a thunderbolt port on any Mac other than maybe the high-end MBP and the Mac Pro. Honestly even the MBP is a stretch. If you are one of the people you're talking about (massive quick storage at any cost), then you aren't going to be using a $1000 form-over-function laptop (11 inch mba).
I was doing video work a few years ago, and we built a fibre-channel system that was pushing 500mb/sec to a 4TB array back when SSDs didn't even exist as a practical idea. Before FW800.
That ran on a dual-proc water-cooled G5 tower.
The equivalent machine that would have the processing power needed to keep up with the thunderbolt interface bandwidth is not available from Apple at all. There is no Mac Pro with a thunderbolt port.
If you want to make the 'well, four years from now...' argument, then look back 5 years ago (TB is now over a year old in mac land) at what Apple as doing (USB 2 and dropping FW400 ports from macbooks) and tell me that the peripherals are going to sit around and wait for prices to come down...
By the time TB products are average-consumer-ready, the 2011 13" macbook pro will be so slow and sad that Apple may not even be supporting it in their upcoming OS. They are dropping support for 2008 models in 2012's OS.
The port itself doubling as a display port is fine, and that was a good idea that makes the concept much easier to swallow, but an HDMI port would have made more sense and probably saved millions of people $50 or more off of a machine that will likely never plug into a real-life thunderbolt device...unless they want to spend as much on an external monitor as they did on their laptop.
Thunderbolt could have been a really elegant and useful docking solution for small Macs. With most announced products being ~50% of the cost of the computer or more, it stops being an "accessory" and starts to become an argument for buying something more flexible.
Can you imagine how many little docking terminals would sell if they were $149 and had DVI, HDMI, Ethernet, eSATA, USB3, FW800, audio in/out and no Thunderbolt out? Just a TB cable that was fused to the box and included in the price.
Basically the updated belkin dock, but at a reasonable price. It would become a defacto standard purchase for anyone with a macbook air or pro.