PWM vs VOLTAGE:
Don't forget the Noctua NH-D14 uses VOLTAGE-controlled fans. My older Gigabyte could control the fans, but my newer Asus couldn't as most motherboards support only PWM fans.
I did manage to get around this issue by using one of my CASE FAN controllers on the motherboard instead. It supported both PWM and Voltage (Asus Sabertooth Z77).
So to be clear on FAN CONTROL for the CPU from the motherboard:
1) PWM
2) Voltage
3) BOTH
4) Doesn't matter (self-contained like the Corsair H80i etc)
Which cooler?
It also matters if you're overclocking and what CPU you use etc. Once you get to $80 I suggest looking into something like the Corsair H80i liquid cooler, but there are many great air coolers as well. There are PROS and CONS to air vs liquid but I still favor air-cooling for most scenarios.
The NH-U14S is a very, very good cooler:
http://www.techpowerup.com/reviews/Noctua/NH-U14S/6.html
It may not be as large as the NH-D14 but the important thing is how well it cools which is very good. Liquid coolers have both a FAN and a PUMP so the Noctua would be QUIETER almost certainly most or all of the time.
*Don't forget to setup your fan control software to create an ideal RAMP profile (i.e. lowest rotation such as 40%, until 40degC then ramp to 100% at 80degC. Just an example.)
SUMMARY:
Unless you have cooling requirements beyond the Noctua NH-U14S capabilities, and your motherboard supports PWM for CPU_FAN I would recommend getting this cooler instead of any other air or liquid cooler.