The NVIDIA GeForce GTX 750 Ti is fast but also power efficient, enough-so that Ryan found it a worthwhile upgrade for cheap desktops with cheap power supplies that were never intended for discrete graphics. Of course, this recommendation is about making the best of what you got; better options probably exist if you are building a PC (or getting one built by a friend or a computer store).
Image Credit: Tom's Hardware
Tom's Hardware went another route: make it fanless.
After wrecking a passively-cooled Radeon HD 7750, which is probably a crime in Texas, they clamped it on to the Maxwell-based GTX 750 Ti. While the cooler was designed for good airflow, they decided to leave it in a completely-enclosed case without fans. Under load, the card reached 80 C within about twenty minutes. The driver backed off performance slightly, 1-3% depending on your frame of reference, but was able to maintain that target temperature.
Now, if only it accepted SLi, this person might be happy.