I've never had a slug but wanted to add from the opposite side of things that any of the "WRT routers" these days seem to play the same sort of role. In particular the Asus WL-500GP does a good job of bridging the gap... low cost, but with 2 USB2.0 ports and full wifi capabilities. It all comes down to questions of purpose though... OMAP3 is awesome for low power media devices (that's what it's designed for after all), but it's not a network access point/storage device/ethernet switch/etc.
If you're looking for something more along the slug lines but with a bit more "beef" in terms of hardware, I found the next logical step is to move up to one of the embedded VIA or x86 boards that will offer you the same sort of network functionality/features, but with some more expansion and performance options: mini-box.com has a great set of them, with the ALIX series being my personal favourites for network-oriented features (and the prices of course are very favourable).