How do I determine what gauge speaker cable I should use with my receiver?

i would use 12 awg size wire. Awg stands for american wire guage. #12 is big enough for home speakers. Monster cable is a common name brand of speaker wire.
Good luck.

i’d like to chime in as an audio professional… with all due respect to srtlhill, i think you should use 14 gauge, and i think you should avoid monster cable.

your HTR-5740 is rated at 660 watts total output. 14 gauge is rated for 5.9 amps, which at 110 volts (wall current) translates to nearly 650 watts. this means that you could use a length of 14 gauge to carry all the power coming out of your receiver. but that power is divided among the various speaker channels, at least left and right if you’re using a stereo configuration, and more is you like surround sound. so 14 gauge will absolutely cut it (unless your speakers are more than, say, 100 feet away from your receiver. they aren’t, are they?)

regarding monster cable, you should go to best buy, or circuit city, or even the dreaded radio shack and compare monster cable to the other offerings. you will notice that monster is much more expensive. what does the money buy you? marketing. that’s all. unless you’re using very high end equipment, the brand of your cable will not matter.

as a point of comparison, we use 10 gauge cable for our heavyweight applications in the theatre. but we also use 1000+ watt amplifiers…

oh man, thanks so much! That’s exactly the info I was looking for.