Because Thunderbolt uses PCI Express signaling, anything you can plug into a PCI Express bus can be turned into a Thunderbolt peripheral. It's up to vendors, but with Apple's adoption of Thunderbolt, I expect to see the same kinds of peripherals offered for ExpressCard/34 (yes, including USB 3.0), and then some. For example, Thunderbolt makes Fibre Channel and 10-gigabit Ethernet practical, creating interesting possibilities for the next Mac Mini server. For the MacBook Pro, Thunderbolt will redefine desktop docking.
As you'd hope given the AMD graphics firepower that Apple built into most MacBook Pros, the Thunderbolt connector is still useful for driving an external monitor. Thunderbolt treats displays as part of the device chain and speaks to them in their native protocol. No special display is necessary, and Apple's standard Mini DisplayPort adapters (for conversion to DVI, dual-link DVI, or HDMI) still work. If you use the HDMI adapter, multichannel digital audio output accompanies video. All MacBook Pro models drive dual-link DVI displays at resolutions up to 2,560 by 1,600. Thunderbolt's there if you need it, but it doesn't get in the way if all you have is a monitor.
Thunderbolt MacBook Pro: A lone issue Wireless networking is well seen to by Broadcom components and well-placed antennas. The MacBook Pro's 802.11a/b/g/n radio is sensitive and power efficient, and Apple's drivers exploit its rapid multiband network scanning. Reconnecting after suspend is impressively quick. Bluetooth handles all worthwhile profiles, enabling tethering/modem, file transfer, serial port emulation, and high-fidelity stereo with remote control.
802.11 did present the single repeatable glitch encountered during my evaluation. Wireless ping tests between MacBook Pro and a Time Capsule base station revealed widely varying latency. In some cases, response packets lagged by more than 250ms -- latency that equates to forever in LAN terms. The lag was not present with an Ethernet connection or with a Hawking HWDN2 external USB Wi-Fi adapter.
I discovered that the problem disappears when the delay between packets is reduced to 200ms. I believe that OS X is aggressively powering down the wireless radio to extend battery life (radio is a major consumer of power), but that's opinion. Apple acknowledged my report and validated my tests, but a fix was neither deemed necessary nor made available by press time. Because the issue does not affect browsing, video or audio streaming, email, or other common network tasks, it may be purely academic, but I will continue to research it.
There's simply too much to say about the difference in user experience between the Core 2 Duo MacBook Pro and the new Thunderbolt Core i7 models. It's my job to transform subjective to objective through benchmarking and other tests, but in the end, what matters is how the machine feels, sounds, and drives.