Spend money on fancy Alpines or Infinity or whatever if you want - the Kenwoods are 95% as good for a fraction of the price. Better than JBL's car audio and Bose, btw. (note - NOT true for home audio - heh)
I actually have a Kenwood subwoofer and amp in the 4Runner along with JBL front speakers. I don't remember what my 6x9s are...
My home audio is the Infinity speakers that I "stole" on eBay. Their retail price was about $1,800 and I purchased them from Infinity Direct speaker with a full warranty for under $500 including shipping. A buddy of mine got a set for about $350 because he was willing to get two left channel speakers so the side firing subs were on the same side. I checked shipping for a set of IL-60 (the big brother) from Colorado to Washington State and it was over $300 so I figure I did well. My dad found a floor model set of IL-60s for another friend of mine in Colorado for about $500+ so I delivered them when I made a trip to visit my parents.
I'm looking forward to getting my Bose headphones, my current cheap Sony ear buds stink.
