Same here - just a little more geeky, with a transparent box. ;-)
For me it's running a couple small utilities and a tincd based network, connecting various machines of my brother and me. Mostly - it's a small always-on playground machine.
The USB/Wifi dongle is interesting. I don't know much about this flavor of adapter, were the drivers already in the kernel? Any problems getting it running?
My Pi is pretty close to my wifi router and I have the same stick - 4-5mb/s depending on what I'm doing with the data. You may need to turn power management off for the device.
I'm very interested to see some benchmarks for this. Given Nginx is pretty minimal in its system load (I think) might it actually be possible to run a reasonable-sized website off one of these servers?
All network interfaces go through the usb stack, a few monthes ago there were issues with usb polling (usb driver being in the closed-source firmware iirc) eating cpu cycles. I don't know if it's been solved since.
I'm not knowledgeable but I can only recall one SoC providing usb3.0, mind you those things are for embedded/phone devices, thus usb3 looks like a costly overkill. I'm all for it but that's hardly a motivation for them.
usb2 would be fine if it was a sane implementation but AFAIK the rpi SoC was made for ~video-only appliances where there's close to no IO or cpu processing and thus the usb stack firmware code do some bold decisions that induce a nice penalty on usb/cpu.
It's possible that they released a new version since (my data dates from a few monthes ago) or that someone published a binary patch to improve the situation.
I think USB 3 is prohibitively expensive at the moment. Power may be an issue there too - you barely get 200mW out of the USB ports by the time the system itself is powered.
Whether or not you're hosting static content would probably play a big factor.
I've got one, and while it is fully functional it is not fast. The network runs over USB, so bandwidth is limited, and latency is never great. Content is stored on the SD card, which is also over USB. Seek times are good but bandwidth is poor.
Me, I'm hoping for a rev2 wherein USB is not used for the system bus and the core is ARMv7 or better. That, or possibly just use NetBSD once it's been fully ported. I've had great luck with BSDs on super-weak hardware.
You would have to define 'reasonable sized' but I suspect the answer is yes. If you mount the web files over the network (I use NFS v3) you can run a very nice Nginx web server instance and a full stack. Not surprisingly, one of the 'bottlenecks' in RasPi is the SD card so using network mounted files is quite a bit faster in my experience.