If you have a newer model flat screen TV, it’s likely pretty thin, which doesn’t leave a lot of room for great speakers. Fortunately, can add a sound bar to greatly improve the sound.
Although you can buy a basic one for as little as $50, you might want to get one with a subwoofer for deeper bass — you can actually feel the action. Also consider one with side or rear speakers for true surround sound. CNET has some recommendations at various price points. One reviewer was very impressed with the Vizio SB36512-F6, which I ordered. Check back for my impressions after it arrives.