Development kit selection for newbie

If you want a SoC - you might be better off looking at the Xilinx Zynq range. Xilinx are way ahead of Altera when it comes to SoCs, and all of their IP supports industry standard AXI (rather than the proprietary Avalon). Altera have AXI/Avalon converters (not for streaming though!!) but it's just more logic that wouldnt be needed over at Xilinx. Altera have now pretty much dropped SoCs - having always pointing you at rocketboards.org if you want any linux support. They are pushing OpenCL harder, which is mostly aimed at processor controller + FPGA co-processor, which will tie in nicely to the fact that Intel is buying Altera (pretty sure you'll see FPGA/x86 dev boards at some point).