I have a cm 690 too, the plan is to fit a 240 in the roof with my two typhoons under the plastic top. then at some point add my gpu to the loop, since oc'ing it has started to sound like a jet. I also dont want to mod the case that would just eat into the little time I have to game. still haven't had the time to measure how much space I have for the rad.
I am currently running a ek 120 kit, might use the 120 rad for everyday use and with the help of a fan controller (corsair link when they deal with their issues) to power the up the fans for the 240 when gaming.
my short list is the hardware labs sr1 and the xspc ex240. I think I have enough space for the ex, not too sure about the sr1 until I get the tape measure out.