| posts: 3,006 | Location: Not Far North Enough (England)
Lot of RAM is good for e-peen and virtualisation, but can be a headache when coming to running it fast (er than 1333/1600 MHz) as larger DIMMS (and more of them) put far greater load on your CPU's memory controller (my 6 DIMMs are rated at 2000 MHz, can only run reasonably at 1600 MHz, only got 24 GB for audio recording). If you need 16 GB for photoshop, get it, if you don't 8 GB should be fine for everything else, including all games you can throw at it, better investing the money in an SSD boot drive, your mobo has SATA 6Gb/s ports on it.
As for cooling, a ruddy great heatsink can be cheaper and perform about the same as an integrated water cooler like the H100. My Noctua NH-D14 is about on par with that in terms of cooling performance going off benches, only problem being you need low profile RAM. AFAIK, the integrated water things are just as easy to install as a standard CPU cooler.
Hope that helps.