I have to be honest I don;t like that case, the CM 690
I prefer windowed cases too, I don't have one but it's good. Personally I'd go for the Lian LI K63B you posted, plenty of cooling power, nice cable management and appearance wise I prefer it. Both are good choices though.
PSU, I personally own a XFX power supply and they are great, good for their price.
As for memory heatsinks, no they aren't really anything fancy unless you want to seriously overclock your RAM. DDR3 RAM runs at a lower temperature than DDR2 at lower voltages too. I have the Corsair XMS, small heatsink on top but got it mainly because of the price. Other than that memory heatsinks are for serious DRAM overclocks.
I heard the GX PSUs from CM aren't too good.