id say it depends on what you plan on doing...i have a lv 19 rouge twink and i chase down people with the flag alot....for that i say icey is the good one because slowing them down helps ALOT...but damage is also just as important....

id say i see firy proc every 3-5 hits
while icey only procs every 20-30 hits

i myself couldnt decide so i went with offhand=icey main=firey...goodluck deciding for yourself...or you could always go crusader rofl.