You will get the best results from training, diet and rest but supplements can help give you a little edge.  If you are just taking supplements and have a bad diet you won't get the results or look you desire.  They are all necessary to achieve your goals.

            Pre Workout Drink: If you are working out twice a day hard, I recommend a pre-workout drink for your lifting workout.  Most pre-workout drinks have caffeine or DMAA (aka geranium root) as their active ingredient.  I usually use a caffeine based pre-workout.  There is not enough research (in my opinion) on long term effects of taking DMAA.  However, there most people do take caffeine in much higher doses than I do in my lifetime. 

            Whey Protein: For post-workout I take a whey based protein shake.  The protein shake is mostly for convenience and allows me to eat another full meal within an hour.  A shake that is a mix of casein and whey is also beneficial for post-workout.

            Casein Protein: Right before bed time I drink a protein shake made of casein.  Casein is a slow digesting protein that fuels your body with muscle building protein while you sleep.  This is my last meal of the day and I usually eat a handful of almonds and/or flax seed with my shake.  The healthy fat also slows digestion further so your body has fuel during the night.

            Multi-vitamin: Usually multi-vitamin is a good idea to make sure you are getting all the necessary vitamins and minerals.  Any major multi-vitamin is fine I usually purchase mine off bodybuilding.com.

Amino Acids:  Amino acids are the building blocks of protein.  If you are looking to spend more money or you want something tasty to drink besides water during the day I would purchase amino acids.  Typically I buy Blox (for the taste) or Scivation Xtend (because it has the essential amino acids and it tastes good).  I will take amino acids before cardio, during lifting or anytime I want something besides water to drink.

            Remember, supplements are exactly what they say…supplements.  They add to your regular diet.  So fix your normal diet first and your training then add supplements to the mix.