Unfortunately, it is hard to state what is best, as everyone's tastes are different. I personally like Syntrax protein powders because they taste good mixed with water. If you like coffee, Click makes both a caffeinated and a decaf protein powder. Finally, Unjury makes a chicken soup flavor that I love.
I have mixed sugar-free syrups and sugar-free pudding mixes with protein powder to change the tastes up a bit; the cheesecake pudding flavor can be yummy. I also mix a scoop of Syntrax Chocolate protein powder with a scoop of mocha Click for a fancy flavored coffee. Finally, I also like to mix a bit of PB2 with the Syntrax chocolate, for a nice peanut-butter/chocolate shake.
I buy most of my protein powders from Nashua Nutrition. They sell protein powder samples for $1.99, which allows you to try out different flavors without investing in a whole container.
As for protein bars, I used to consume a lot of Pure Protein until I grew tired of them. PowerCrunch wafers are tasty as are Quest bars, but Quest bars are pricey and very, very dense.
Total Weight Loss (HW 5/2010)
Post WLS (8/1/2011)