Something that would be good for vocals and/or accoustic guitar . . . the one that comes to mind would be the Audio Technica 4033. It's not sold any more, but I'm sure you can find one easily on ebay if you're in to the ebay thing.
Otherwise, you should probably understand that what sounds best on acc. guitar won't necessarily sound best on the human voice and vice versa. A better setup might be a small-diaphragm condenser for acc. guitar (Oktava mc012 ?), and a Large-diaphragm condenser for vocals (whatever sounds good on your voice and fits your price range).