You must have chosen poor speakers PaperBoy if you don't think you hear a huge difference in sound quality. You need to choose a speaker rated accordingly to work well with the OEM head unit.
The OEM speakers are basic full range with no lows, mids, or highs. I bought some JL Audio 6 1/2 two-ways for the front doors and 6x9 three-ways (the two-way models don't fit in the rear deck) for the rear deck and the improvement in sound is exceptional. I get deeper bass and clearer highs from all four speakers and I spent less than $200 to do it. Replacing the speakers is an inexpensive and easy way to improve your sound with the OEM head unit.
See the thread here, but ignore most of the follow up threads since the majority of people went completely off topic and think you can only get good sound by spending thousands on multiple amps and subwoofers, which is clearly not true. They missed the point of the thread which was improving your sound on a budget.
http://www.driveaccord.net/forums/showthread.php?t=33700