The thing with Gentle Typhoons is that they don't simply perform well at low speeds, the sound that they give out when they are running fast is tolerable. It's different from other fans - more like a loud whisper than a whirring noise. Personally, I use three AP-15's with a Kaze Master (the same one lynxxyarly linked in the post above this one). I have them turned down to around 1400 RPM or so and I really can't hear them. They're very pleasant.
I would get some Gentle Typhoons first then invest in a fan controller anyway when you can afford it. I ran my AP-15's without a fan controller for a month or two and the sound honestly isn't that bad. You could even go for AP-14's which run slower at stock and will perform very well. I have my AP-15's turned down to AP-14 speed anyway with my RX360 and the temperatures on my CPU and GPU are well within reason. You have to have some kind of compromise between sound and performance to achieve what you bought water cooling for in the first place - it's all about what you
Also another note on fan controller: Take a look at a Sunbeam Rheobus. They have like 20W per channel which means you can hook your pump up to it too to control the speed/noise of it - the Kaze Master's only have around 10W (I think) per channel - they won't support the pump too.Edited by jNSK - 4/26/11 at 1:03am