Best Jigsaw and Circ saw blades for MDF?

For jigsaw blades I think I use the rough or fast cut blades, and what ever came with my circular saw works fine.

MDF dulls blades fast so I genrerally buy the cheapest blades and do a little sanding to finish off the project.

If you're buying a new blade for the purpose, I would suggest the 40-tooth fine blade.  But either 40- or 24-tooth will do the job.  The keys are to use carbide-tipped blades and set the depth so that the blade barely passes through the thickness of the wood (blade depth set to 3/4+ instead of 1 1/4").  You want the teeth cutting wood at that point, and not entirely out of the wood.  This provides for the smoothest cut.  Cut through slowly enough that you don't get a lot of burn marks on the wood. 

For a jigsaw, a combination or fine wood blade.  Also, look for expansion grooves built into the circular saw blade.  Don't buy a cheap blade that doesn't have these.