Check out the following project. It is a PIC24F based development board which has few great features including USB, Ethernet and micro SD card. For Ethernet interface there is ENC28J60 chip used while USB is an Internal peripheral of PIC. Overall board is quite compact and still powerful.
To be fully functional development platform, board has an expansion header where several expanders can be connected. Some of them are finished like touch keyboard, TV output and PS/2 PC keyboard, LCD, Temperature sensor. Probably best of it is web feature, where board can be accessed via WEB interface from anywhere in the world.