Generally, you should try to avoid "additives." One of the reasons to brew your own beer is to have control over what goes in it. (Or, better yet, was doesn't go in it). While you certainly don't need to adhere to the German beer purity laws, in general simple is better. When you are making 5 gallon batches you can afford to put only the best of ingredients in your beer. I use Irish moss, but that's about all that goes in my beer besides water, yeast, malt and hops. I may eventually try a pumpkin ale or a raspberry or something like that, but mostly I just want to make good beer.