I don't know what the clearances are in the 7th gen accords, but the 6th gen has plenty of room for a decent set of both front and rear deck speakers. I've gone with Polk and Soundstream and they are both excellent. The Soundstream have big ol magnets on them too and they still fit with no problem though again, I don't know if the 6th gens have a bit more clearance in the front than the 7th. Either way, yeah, get rid of those crappy stock speakers ASAP. Soundstream tarantula's (top end) go for around $90 for 6x9's, $50 for 6 inchers on eBay (that's the size for 6th gen's, check for 7th gens). Polk is more expensive but sound a little crisper IMO. Soundstream put's out a bit more bass though.

After that, consider spending $130 or so on a new deck. Unless you want all the funky bells and whistles, an entry level pioneer or alpine deck will last for a long time, will play MP3's, WMA, etc., and will put out WAY better than whatever Honda stuck in your car.

A new set of speakers and a new deck will give you plenty of kick. If you still want more low end bass, consider a entry level amp and sub. Don't spend a thousand bucks on it though. Some people get a 2000 watt amp with two 15 inch subs. That's stupid. You're speding money so someone else (who probably doesn't want to) hear your music. Get a little 8 or 10 inch sub, maybe a bazooka enclosed sub or something, and a 500w or so amp. You won't spend more than maybe $200 on eBay or amazon for that. It will get you lot's of low end bass without shaking your car apart.

All in all you've spent around $500 (or less if you shop around) for a kickass system that will last for at least half a decade and will make you look forward to commuting but at the same time, won't piss off the guy next to you at the stop light or label your car as "steal me! my car audio system is worth more than the car!". Good luck!