One problem about asking for opinions on speakers is that you'll hear very subjective terms, "good", "great", "excellent", all subjective terms.
The best thing to do is to go to as many car audio shops and listen to the speakers that you're most interested in and that YOU think sound good. That way when you buy them you aren't disappointed because someone else thought they sounded "good". Another thing to keep in mind is that most after market speakers are made to be amplified, so if you're using your head unit to power them, don't be surprised if the speakers you end up buying don't sound as good as the ones they had on demo.