CDT HD-642DTM with the mid and tweet in kick panels, or just HD62-DTM and find a happy home for the tweet, of if you have some cash to spend, some ES-643(euro sport series), or if you're on a budget but still want some serious sound, the CL(classic) series is definatley pretty damn nice, or for the serious budget minded the classic slimline coax that were previously mentioned sound fantastic for a coax. I was running the HD-642s up front and cambria 6.5"s in an adapter plate for rear fill, sounded great, but had a booboo(crappy ripped mp3, and gain up too high on the amps) and one side of the cdts bought the big one, but I just ordered another set. I love CDT if you can't tell, a lot of bang for buck. Infinity Perfect 6.1s are ok, I think the cdts outperform them for less money though, but the Infinity driver look better to the eye. I have kicker RS6c in right now, and for the money they aren't bad, just not my favorite drivers around, tinny highs, and muddy mid, bleck.. Fosgate fanatic Q sound pretty decent, but again I've heard better for the money. All other fosgate lines are worthless to me. Focal are definately up there on my list as well, polyglass are great for them money, so are poly kevlar, but if you're serious about your tunes utopia are definately some nice drivers. Oz matrix line is pretty decent too.

Best bet is to go out and listen to some, it's hard to take other people's word for something, what sounds great to one person might sound like dung to another, and vice versa. Audio is one thing that's definately up to the end user. While folks like me that have been listening to nice systems for ages might not be able to stomach a set of infinity reference, they might sound good enough for your. Again, just go listen to some.