What's the one you're using like and what do you wish was different about it?  The most important thing at your stage of the game is to have something that doesn't get in the way of your playing, i.e. is easy to blow on.  As your embouchure develops, you will be able to handle harder reeds, larger tip openings, and larger chambers to strengthen your sound in the ways that you want.  But the most important element is you and the strength of your playing.  When the time comes when you're reaching for *that* sound, always consider your technique first.  The best mouthpiece in the world won't generate a good sound if the player doesn't generate a good sound. 

Looking for the magic mouthpiece to transform one's sound is a trap a lot of developing players fall into.  Stick with the basics as far as mouthpieces go and you will become a stronger player.