Eddie, for line, around here, we run the .095 from Wal Mart. $17 or so for a 3 pound roll, works real well. I think it is shakespear line.
We find running the 105 around the chain link that it cuts it off to quick, the 95 has a bit more give and works better in our application triming around homes.
If you want something slick, get one of the new Shindawa heads, I forget what they are called, but you cut your string, pass it through the head to the halfway point and then wind the head like a watch and it auto spools it up (you have to do it often to appreciate this feature)
Champy, sure, you can run whatever you can mount on the end, and it will work to a degree, but the idea of that little gearbox shredding itself and the blade coming off is enough to scare me away from doing it.
There are MANY adapter sets etc. out there, but I would only want a blade running on a fairly stout trimmer, and even then, to be honest, they scare me enough I usually look for other ways of doing things.
(We trim the trails at our event and we have tried it a number of ways)