I have a 01 accord ex-L which had done about 120K. Its got a 6 CD changer and the old cassette tape. However the CD changer stopped working a while back and I was looking to get it replaced.
I want to have good clarity and some bass in the music I listen to. But I am not sure if only changing the stock stereo player will help me achieve this. Do I need to get a small sub-woofer and an amplifier? If the stereo that I purchase has a small built-in amp will that be enough?

I'm getting tired of these questions so I'm going to keep it short, when you search you will find more than enough info. This is hands down the most discussed topic. Stock headunits have a built in EQ to make the subs sound "boomy" this destroys audio quality with real speakers. The built in amp on ANY HU is not enough power for most speakers, and efficient low power speakers still don't sound so hot with 15 watts. If you are looking for bass than you need a sub, you will only be disappointed by the bass output from speakers. Most quality speakers are designed with a sub in mind.

Thanks