I've been looking a bit into low-end ethernet options for JeeNodes. Lots of ways to get there. Say you want to tie a "real" computer together with a bunch of wireless sensor nodes without hacking/re-purposing something like a router or NAS, and without dedicating yet another embedded computer to it, i.e. truly low-end. With a JeeLink / USB, the distance is limited to a few meters.
The ENC28J60 chip could be used. It's been around for a while - it requires a lot of software support from the ATmega to do things like playing nice with DHCP, acting as a very little HTTP web-server, or pushing results to another TCP/IP server. So the hardware is simple, but the software might be hairy (to make it fit, to make it extensible enough, or even just to configure).
This isn't instead of hooking up some embedded Linux with Ethernet - I'm just trying to figure out whether a lower-end option could/would/should be justified.