I have VARIVAS Super Trout Advance Sight Edition on all of my rods that are strung with 3,4,5,and 6 lb test lines for freshwater fishing and really like it. I only use mono. STA is slick, limp, casts well and very easy to see.

STA is expensive, but is the best light line I have used, along with Sunline Neo-Technician in 7 lb test. Sunline Supernatural in orange color is my favorite for 8 lb and up. It is a lot cheaper, and still a very good mono.