Which CPU Cooler?

Whats your budget for your cooler?

My recommendation (I know you probably don't want this):

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU Cooler: Corsair H80i 77.0 CFM Liquid CPU Cooler ($86.99 @ Amazon)
Total: $86.99
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-09-29 00:54 EDT-0400)

Otherwise:

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU Cooler: Noctua NH-L9i 57.5 CFM CPU Cooler ($47.99 @ Amazon)
Total: $47.99
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-09-29 00:55 EDT-0400)

While the water cooler would keep it much cooler, if you can push your budget it would be worth it, otherwise if not i would fully recommend the air cooler (its quite thin, and its from a very good brand). Also please remember to select the best solution so that others may learn from this thread. Thank you for your time.

I can't speak for water-cooling. I haven't done as much research into it as I have air-cooling, not to even mention actual dabbling.

The ETS-T40 is a good cooler. I have the TB variant of it (no frills, base model that cost $35 bucks) and I am happy with it. The W and BK variants that just came out, with the ceramic coating, do supposedly work better, but I am not exactly sure by how much. There is no apples-to-apples comparison between the two models yet, and I can't afford to toss $50 out the window to find out for posterity. I doubt the difference is a world of difference, probably a handful of degrees at most. Anyway, the only negative with the ETS-T40 is that it is a product of it's time: it was designed and made when Direct-Touch heatpipes were first becoming a trend, so it has the first generation design of that. If you look at the base, you'll see that the heatpipes are separated by aluminum "slabs", as opposed to uninterrupted. It could be argued, with some evidence, that this is not conducive to extreme enthusiast overclocking. Up until you reach that point of enthusiast overclocking, though, it tends to be an outstanding cooler that can play with the big boys, to a degree. (I'm short on time, but, I'll try to provide links later.)

The Phanteks is generally received positively. At worst, it will probably operate around the level of the Cooler Master Hyper 212 EVO (and, by corollary, the ETS-T40). In some other reviews, it approaches the level of the Noctua NH-D14, if I recall correctly, although I can't remember how heavy the overclock was.

Long story short: the Phanteks probably is the safer investment since you plan for a heavy overclock. Otherwise, the difference won't be phenomenal. Again, I'll try to provide links later. (Have to get ready for work.)

Right, so first off, I am going to deal with the subject of the ETS-T40 and its design. Here are the two links from a site called Vortez that I am providing for main source material:
http://www.vortez.net/articles_pages/cooler_master_hyper_212_evo_cpu_cooler_review,8.html
http://www.vortez.net/articles_pages/cooler_master_hyper_212_evo_cpu_cooler_review,11.html

The first link is to stock configuration results (an I7-920, with a TDP of 130w, at 2.66ghz) and the second is to the overclocked results (at 4ghz.) You'll note I actually have the results for the Hyper 212 EVO linked, that's because it's a popular cooler to reference, and also because, using the same rig, there are also the results for the Enermax ETS-T40 and the Cooler Master Hyper 212 Plus. Looking at these results, you can see that the larger surface area and other improvements of the ETS-T40 give it an advantage at stock settings, but when you crank it up to that heavy overclock, it struggles to surpass the Hyper 212 Plus - it can not out-pace it beyond the margin of error (generally taken to be about 2C). Meanwhile, best case scenario for both cooling solutions, the Hyper 212 EVO manages to break beyond the margin of error ahead of the ETS-T40. So this shows fairly well how, although its a good quality cooler, there is an inefficiency (the first generation base design) that doesn't allow it to take full advantage of what it could offer. The inefficiency doesn't look so bad, though, until you run into this: http://www.tomshardware.com/reviews/LGA-2011-i7-3960X-Air-Overclocking,3130-17.html where, for whatever reason, Enermax's option tanked while the Hyper 212 EVO held its ground almost too well. Even if it's a fluke, it's a result one can't exactly ignore, because somehow or another that physically happened and was recorded. (Hopefully, it wasn't a case of a lack of quality control on Enermax's part.)

That's with the Enermax option *without* ceramic coating, though. Like said before, I doubt that it'll make a huge difference, I can only imagine it helping out by a couple degrees. Until we see reviews that is brave enough to do an apples-to-apples comparison, all we have is conjecture.

As for the Phanteks, that Vortez site shows it operating within a couple degrees of the Noctua NH-D14 and NH-U14S, both which are pretty big hitters, even when the rig is overclocked. While I don't doubt it's a good cooling solution, I wouldn't expect to necessarily get the exact same results, especially since we have data like this to cross-reference: http://www.hardwaresecrets.com/article/Enermax-ETS-T40-White-Cluster-CPU-Cooler-Review/1783/6
(Thanks, HardwareSecrets, for throwing a wrench into the works.)