You know, I think you're right.
I've only tried the lighter-test lines, and I had a heck of a time making the connection. My uni-to-uni and albright knots were all busting. I just thought I was using too thin of a line. I think I need to take your advice and use pline. Thanks!
In saltwater fishing, I usually use Seaguar lines and they are good. There's a relatively new company called Blackwater - they make some good stuff, but I believe it's for larger fish.