well for starters i have a HAF 932 as well and the watercooling itself cost me about 400-500 bucks so just make sure you have the money set out for it
one thing i would suggest on the video cards, i recommend you stick with a single card so you dont have to pay extra, my single 5970s block cost 145 versus 220ish for two 5870 blocks. maybe you should wait for the 6990?
im not exactly an expert but if you arent using a radiator based watercooling system then thats probably phase change or something that i have no idea about i think watercooling is your best bet for 24/7 use
i dont have alot of experience with the bay controllers but my NZXT sentry LX is pretty awesome, it hast temp probes that seem pretty acurate (havent used them personally, makes the case look messy)