If you listen to a lot of music then get a new headunit for sure. The stock speakers should be pretty good considering it's a 2000. Accord is considered more of a family sedan instead of a sport compact, I'd leave it at that.
I'd only put money into it if it had a h22 Vtakkk, but it most likely dosen't.
Like everyone said, keep it until you get something a little more worthwhile and sporty.