Good advice stasher1.
Also, you can go up or down one weight of fly line for the rod rating. I use 6 weight line on my 7 weight rod. I could get more casting distance going the other way, but I like to fish for crappie and sunfish as well with small flies and I only have the one fly rig, so it has to be able to do it all for me. I take this fly setup as well as baitcast rigs in medium, medium-heavy, and heavy, and spinning rigs in light, medium-light, and medium on my fishing trips.