Mac OS X comes with a great font manager called Font Book; it’s in your Applications folder. With it you can view text samples of all your fonts, enable and disable fonts, create and manage collections of fonts, and even print font samples. I’d highly recommend checking it out before you turn to third-party applications.
Update: I suppose it might not be immediately apparent, so to sample fonts with your choice of text, choose Preview → Custom (or press ⌘3). Then you can type whatever you want in the preview column on the right.