I use 10# braid with a 6-10# Trilene 100% fluoro leader personally. The only reason I use the particular fluoro is because I get it in the little bitty spools on clearance at walmart from time to time and it hasnt given me any issues.

I use the Alberto knot to connect them.. The alberto knot does get big though if you use it on anything above about 12# test or so, which is when I resort to the double uni.
Both are great knots.