Per Condello's recommendation, I am currently using 4 lbs Trilene on my ultralight. But I understand there are definite advantages to the more advanced lines (flouro, braided, etc.) which I am sure you will get to hear about shortly.
P.S. You're asking a bunch of chubby kids what they like best about the candy store!
"Live like you'll die tomorrow, but manage your grass like you'll live forever." -S. M. Stirling