I just replaced the speakers with Infinity Reference speakers, 6x9's in the rear and components in the front. I just put the woofers in the front and I'm still running the stock tweeters. Sound quality is much improved and I hope it'll sound even better once I get around to putting in an amp and put up the Infinity tweeters.
BTW, I had Infinity Reference speakers in my 96' Prelude VTEC for a couple of years and then I replaced them with Kappas. Maybe it's just me, but I really can't tell much difference between the two. I would strongly suggest you go somewhere to audition some speakers to find out which ones you like.
Then, again, the 6x9's were on clearance for $60 at Crutchfield and I just couldn't resist!