I could tell you that I love D’Addario’s Silk and Steel (EJ40) and that you should buy these for their awesome mellow tone, but it really depends what you are looking for or would like to try next. There are a number of variations on guitar strings, and each one offers something else (most of them neither better nor worse than the other, just different).
D’addario Coated contain a layer of protective material over the wound strings (usually the 6th, 5th, and 4th, which are the three closest to your chin). This protective coating helps keep down on the collection of dirt, skin oils, and grime. It also slows down normal wear and tear. With all this extra protection, you get that bright, new tone far longer than you do with the uncoated sets. With the longer string life, comes a higher price, but if you like them, it’s definitely worth the few extra dollars.
One thing that some people don’t like about the coated string is that they are slicker on the fingers than normal ones. This is actually a good thing, as it helps reduce the amount of fret noise and string squeaks as you play.
D’Addario EXPs (but these are actually my favorite coated string!)
Past coated and uncoated sets, there are many variations of guitar strings. Some of these are available in coated variations, but for the most part I’ll suggest the non-coated ones below.
80/20 Bronze – This is how guitar strings were originally made, and they are often a popular choice today. Using a mixture of 80% copper and 20% tin, the sound out of the box is going to be slightly brighter than any of the other type of string mentioned here.
Phosphor Bronze – These are probably the most common guitar strings. They were first made popular by D’Addario in the 1970s. Composed of 100% bronze, they have a bright, warm tone and a balanced sound.
Nylon – Nylon strings are used on classical guitars (like the Takamine EG128SC). The tone is going to be very warm, and the tension is going to be relaxed on the guitar. Most guitarists would frown upon putting these on a steel string guitar.
D’Addario EXP46 (this is actually a coated nylon string!)
Flatwound – Flatwound strings use a squared wire wrapping on the wrapped strings (the 6th, 5th, and 4th strings). This makes it more resistant to dirt and grime buildup, giving the string a little more time before being replaced. The feeling of the string is easier on the fingers, and the tone is slightly different from usual strings.
Silk and Steel – If you want something mellow, go with these. Perfect for folk music applications and smaller guitars, these string set feature the use of silk in the copper to give that mellow, hushed tone that’s excellent for fingerpicking. They won’t be as loud as all-metal strings, but the sound of the guitar will really shine.
D’Addario EJ40 (I always have a set of these around.)