For years, when trolling with mono, I use mostly Berkley Trilene XT in 10 pound test. It is very abrasion resistant. I stick with the clear or Green. XT is not a real expensive line, so you can afford to re-spool more often to keep fresh line in play.
There are times I use Berkley FireLine (also in 10 pound test) for trolling for a couple of reasons. For flat-lining this no stretch line will transmit the lures action to my rod tip so I can more easily monitor if the lure has got fouled (weeds, Zebra Mussels, etc). On board fishing, FireLine is useful to get crankbaits to dive deeper because it is such low diameter (10# FireLine is same diameter as 4# mono). The Precision Trolling Book charts the precise difference, but for many cranks it can mean up to 30% more depth which can be just the extra depth needed to get down to the fish.
If you do use FireLine on boards (I use Off Shore Tackle OR-12 Side Planers), you will have to either double wrap the lines on the conventional releases or go to a release like the OR18, or “Snapper Release” (Click Here to learn More) www.offshoretackle.com/OR18.html. This release has an adjusting screw on the bottom so you can tighten it so even thin/slippery FireLine will stay in place.
One thing to remember, don’t use FireLine is you are Open Water spinner fishing – stick with 10XT/Mono.