I was thinking that an easy addition to the server would be to add a temp sensor to the board to allow the webserver to show the current temp and log temps etc.
i guess taking it further you could add a humidity sensor etc.
A 1 wire buss temp sensor could be added and allow multiple temp sensors using just one i/o pin.
for example the 18s20 and the 18b20 chips are cheap and easy.
Tempreature and humidity sound great targets for this.
In fact, I have a low priority project to do this but with a ATMEGA32 and ATMEGA128 as that's what I have and what tools I'm familiar with (although perhaps with bp3 on the way this might change). I want to simply have my device as a web end-point that can be interrogated by a weather focussed PC application (yet to decide on what one I might use) and to report temperatures in a couple of places around the house. [as a side note if any one has pointers/thoughts on how best to handle the "response" part of this, for multiple devices, I'd be interested to hear]
The one thing I like about this platform over the atmel one is the TCP/IP library, it seems to me that its much more comprehensive than any of the public ones.