Another suggestion would be to buy what you like model wise and enjoy the fluff that goes along with it win or lose! Adapt your strategies to fit your army and learn as you go along. Half the fun is having an army that you're proud of modelling and that you enjoy the looks, fluff and use of! You're going to lose alot until you figure out how you can play whatever army you choose! Don't worry about that, don't expect too much the first few times, learn, and best of all enjoy! Most people just want a hard hitting army that doesn't lose, and well they get frustrated when they don't win right away! Enjoy whatever army you start up and learn as you go, that's my advice really!