Big fan of floro leaders. I use 100lb Berkley Big Game on my tip ups (quick strike rigs), and have used it in the summer as well. By the end of the winter season my rigs feel like sandpaper and look like they should break by just breathing on them, but I'm sure I could get alot more use from them if I wanted to. I crimp mine as I can't tie a knot with the heavy stuff that I'm comfortable with. One trick with the crimps is to melt the tag end a bit so it mushrooms, and will be harder to pull through the crimp sleeve. I also run the tag end back through a second time as insurance. Also I use these Scotty downrigger sleeves...
http://scotty.com/fishing-gear-equip...sConnector.gif