I use the bulk Golden Flax Seeds from Wild Oats/Whole Foods, fill up to the blades in a coffee grinder (around 2 tbs), grind, then add to a whey shake. To me it tastes fine. If I'm in a hurry I'll just add the ground flax to a 1/2 cup of water, drink and go.
I don't like the taste of flax oil, so I don't use that in shakes but I'll use the flax caps as a supplement.
I like the benefit of using the ground flax for fiber as stated in the above posts, and the 'golden' flax type seeds tastes the best to me.