Nylon strings can be used on regular acoustic guitars with wonderful results. I began playing on a classical guitar but loved the feel of the nylon strings so I continued to use them on standard acoustic guitars.
An
acoustic guitar with high action is usually best. Nylon strings usually have a lower amount of
tension, and therefore a wider
amplitude when vibrating. The sound of nylon strings contains more bass and does not
sustain as long as standard electric/acoustic strings. The amount of force required to
fret a note or to bend the strings is lower as well. When strumming an
accented note or chord the strings have a sharper sound that contrasts to their normally dull sound.
When stringing an acoustic or classical guitar with nylon strings it takes quite a bit more work than standard strings. The strings will have a twang that will quickly fade as the strings stretch. The strings will not stay in tune until the strings have been properly stretched. The best way to do this is gently pull the strings away from the fret board one at a time. Pull from different points on the fret board and try to stretch each segment of the string. Typically it takes a few days of playing before the strings start sounding properly.
My favorite brand to use is Darco, but
D'Addario also makes some very good sounding nylon strings.