which board to buy altera FPGA

Hello

I am a bit confused on which FPGA board should i be buying for research and learning purposes

I have found the

DE1-SoC board from altera to contain a lot of advanced technologies + a dual core arm processor at a reasonable price of 190$

http://www.terasic.com.tw/cgi-bin/pa...o=836&partno=2

and the DE2i-150 which is a great board with an intel hyper threading processor that expands the learning to a more interesting field in using intel processors and hardware this one costs a lot at about 600$

http://www.terasic.com.tw/cgi-bin/pa...o=529&partno=2

i have also taken a look at this board the DE2-115 which is great and contains all educational needs but a bit lower end than the other at a 595$

which is still expensive a bit

http://www.terasic.com.tw/cgi-bin/pa...yno=139&no=502

so which one do you think is the most advanced and in which you can use to accomplish higher levels of learning and design ?