Night Caps come today and I've got PC water cooling supplies and sleeving stuff en route as well.
man, I wanna try watercooling at some point.
Short version: Not worth it, but I know you will do it anyways.
Explanation plus little rant:
Modern CPU coolers (even the 40 Euro ones) are really silent and have enough cooling power for everything you might throw at them. GPU's are a different thing, watercooling GPU's really does improve both Temps and noise a lot, the thing is, to get a watercooling setup done in a way that it is not louder than a good aircooled setup at idle costs a lot of work and money. There is so much stuff you could spend the money on instead that would make a lot more of a difference. But, once you go watercooled you don't really want to go back, even if it doesn't make much of a difference it looks way too fancy to not keep it.
Also, if you ever have to change your GPU you'll have to pay for a new waterblock for it (if it is a different model), but more importantly you have to drain the whole System which I find really annoying. I still miss my HD7970 (RIP), the GTX970 could never replace it and performs worse in a few cases, so I never went the extra
mile kilometer (and 200 Euros) to grab a waterblock and backplate for it, now I'm stuck with a watercooling setup that is overkill (I'm talking 240x120x60 and 360x120x60 rads) for just my CPU and limits airflow too much to achieve good GPU temps.