Fireline, tried the silk once and prolly wont ever use it again. The silk was very stiff and made me think of fly line. The fireline is great until winter when it freezes as red mentioned and makes a huge mess, I use the fireline in the summer (10 lb) and my spare spool is rigged with berkley XT 6lb dark green. If your using the fireline be sure to tie a palomar knot, clinch knots tend to slide through if you do not wrap enough and the palomar is a stronger knot anyway, its smaller, and doesnt slip even with the fireline.