I've seen a lot of people just use a double square knot,, but I prefer to use a Uni-knot (also shown in the page linked to above). I've never even come close to getting spooled by a fish, but if I ever do, I don't want to lose him because of a weak knot joining my line to my spool. Your line will break before that knot comes loose. That would be an aweful feeling having a fish run out your line only to have the knot at the spool pull loose. :wall: I also tend to leave the tag end a little longer than usual and let it get covered up by the first few wraps around the spool.
That's my :twocents: Hope it helps!!