I completely agree with Sagefisher.

Rio Gold is a great line. Well suited for dries and fishing smaller stuff.
Of course, you can nymph fish with it as well.

But if you are going to be doing mainly nymphing and/or bigger, heavier stuff, the Rio Indicator line is great.
I own both lines. I use the Rio gold on 4 & 5 wt rods. I use the Rio Indicator line on a 6wt Winston BIIx.

Brian