If you get any of the H series water coolers make it the H100, its the only one worth getting, but if you were to get it you might as well get the Noctua NH-D14, it performs similary and is quite a bit cheaper.
if you do go the water cooling route and didnt want to spend aot of money on a full custom loop, i suggest getting the Rasa RX360 kit or the RS360. its a great water cooling kit, im using the RS360 myself and have had my 3930K up to 5GHz and it doesnt top 75C
i have a GTX680 and beleive me, it performs better then the 670, especially if you overclock the card.
ill post some benchmarks i made with my friends Gigabyte GTX670 Windforce and my Asus GTX680 Reference card below:
be sure to look at the Graphics score
Overclocked Windforce GTX670: (Graphics score 9206)
Overclocked GTX680 Reference: (Graphics score 10912)