From my experience not much beats good old dowels and titebond, the dowels I use for alignment and titebond 2 or better for the joint itself. Don;t forget weights or clamps to hold while it dries.
A good joint the joint will be stronger than the mdf itself.
To make it really easy you can buy a cheap dowel pin alignment metal peg for a buck or two, drill one hole, stick the alighment thing in the hole, press it against where you are going to make the other end of the dowel hole then drill using the guide spot. Easy peasy.
Old school woodworking actually works better than new fangled stuff often, so dont be afraid of what seems too simple to work.
Usually someone also asks about what kind of yellow or elmers glue to use, just get whats appropriate for your climate, water resistant works better in higher humidity. There are situations where poly is appropriate, make your own decision. If you bring new wood/mdf home from the store be sure to let it "acclimate" a bit to where you are going to use it, wood shrinks and expands based on humidity.
Some tidbits anyway that work for me, but keep in mind lots of things that work for one person do not work for another, so let your own instincts choose from all available options.
Brian
