You need to be careful about having a generic brand. A competitor/impostor/parasite can -- no, will, it's inevitable -- slightly tweak your name (say, as cellphonewarehouse). He'll steal your business, the goodwill you've built up through years of advertising and your carefully nurtured reputation, by confusing the public into thinking he's you. And you'll be powerless to stop him, with no legal recourse whatsoever.
Ref Mil-Mar Shoe v. Shonac, 75 F. 3d 1153 (7th Cir. 1996): 'Warehouse Shoes' held to be generic for a place where shoes are sold