I started with a Digilent Basys2[0], it could be a slightly cheaper alternative to the Terasic DE0. It uses a Xilinx chip, has a free design/development software called ISE Webpack, which also has schematic diagram support.
Unfortunately, it still relies on the same Xilinx ISE (webpack is sufficient), so, it's not possible to cook bitfiles on the Pi itself. But the board itself is nice, easily programmable via SPI, has a decent Spartan6 LX9.
[0] http://www.digilentinc.com/Products/Detail.cfm?Prod=BASYS2&N...