Depending on the model I fly on everything from 30-70 foot wires.
Whats more important to me when purchasing lines is to get the propper diameter.
You dont want to be flying a .35 engine on .008 1/2a wire.
I also have some kevlar spools here as well. Havent used any of them yet as I just ran across them in a hobby shop a few weeks ago.
There was once a recomended wire size chart floating around on the net.
I fly my smaller engines .049-.15 on 30% cool Power heli fuel with one ounce of sig castor added per gallon. These however will also run just fine on off the shelf sport fuel. My larger engines I fly on normal 10-15% sport fuel. I also add another ounce of castor per gallon to it, just due to the fact that some of my engines are older and like the added castor. Newer engines run fine on sport fuel. Just watch the lean end of things
I havent had any issues with any of my modern engines. Some engines can be retrofitted with muffler depending on your flying field. I fly many of mine without still as I have no problems with noise issues anywhere I fly.

Most the cable sets I have were manufactured/branded by Sig. Not sure if they still distribute them as I purchase them when ever I see one in a hobby shop laying around.