I use the Castwell knot!
I used it while landing 30"+ northern this
past June and it never failed me. I've also landed several 20"+ WV browntrout using this knot and will never use anything else. Its easy to learn, impossible to forget, very strong, and goes through you guides like there wasn't even a knot there!
check it out, its under the flyfishing basics section, under "knots".

browntrout

[This message has been edited by WV browntrout (edited 26 August 2005).]