For your setup, looking to cool 2x GTX285's, and an i7 your going to need some serious radiator.
We're talk about something like dual MCR320's or a feser/thermochill/XSPC RSX 120.3 radiator at a minimum.
Unfortunately the Antec 1200 really wasn't designed for hardcore water cooling and you won't be able to install it stock.
How good are you with tools and the such? If your comfortable with using a hole saw to cut into the top panel of certain cases you can mount radiators there.
I'll look through some assorted cases and see If I can't find you a few options.
Now for the other water cooling loop parts.
Laing DDC 3.2 Pump with XSPC restop.
Swiftech GTZ Cpu Block.
EK GTX285 blocks, they come in several flavors of the different variations of acrylic, delrin, copper, nickle plated copper.
Compression fittings are nice, but expensive, if that's too much for you, Bitspower Fatboys paired with worm drive clamps are the way to go.
Tubing, for no maintenance Tygon Norprene A-60-G, 1/2'' ID, 3/4'' OD
Otherwise look at Feser's colored tubing.
For coolant, use pure distilled water with Petra's Tech Shop
PT Nuke PHN additive.
Any other questions feel free to pm, message, or email me.