Should I upgrade my towers?


Hey everyone, I recently upgraded my 10+ yr old H&K AVR and Klipsch Synergy towers with a Cambridge Audio CXR200 and Wharfedale Reva-4 towers. I think they sound pretty good together, but admittedly, I know nothing about sound.
Up untill recently, I mainly was only focused on HT. Now, I stream Apply Music to my CXR200 and I love it! I find myself listening to a lot of music on it. 

Now, I'm wondering if I should upgrade my towers? Am I missing anything with these towers compared to better towers? If I went to say $4k towers (pair), would I get significantly better quality sound? I'm more than willing to buy a used set here on Audiogon too. I would keep my CXR either way. Btw, it puts out 170 wpc in stereo at 8 ohms. 

Any thoughts on upgrading, or just keep what I have? Thanks everyone. 
manofsteelpt
Any suggestions? I read the Focals are high in sensitivity... maybe a newer version of a Klipsch?
Once again, you really have to listen to them.
Since you don't have a local dealer, maybe you can try manufacturers who offer a trial period.
I know Zu, Magnepan, and Tekton offer trials. You just have to pay for return shipping.
I haven't heard Focal's, and I haven't heard Klipsch in decades. Though in my opinion, I think you could do better.
Sensitivity only relates to how easy they will be powered. How they sound to you is another matter.
B
Focal Aria 936 would be great in your price range, but there are hundreds of speakers out there to research and audition.  The problem with Focal is that there are so few brick and mortar shops that have them for audition.  Paradigm and Klipsch are much easier to find.  If your Best Buy has a Magnolia in it, then they will have some nice speakers to check out.  Revel Performa 206 is also another nice one to check out.  Monitor Audio, B&W, KEF, and Golden Ear are other companies to check out.
$4k used speakers will put you in another world sonically.  Absolutely upgrade!  Since you're relatively new to this, if you buy used I'd try to go with something that's not extreme one way or the other and that tends to shoot straight down the audio fairway.  Some brands that many people like and rarely get negative comments (off the top of my head) are Joseph Audio, ProAc, and Silverline.  There are a couple pairs of Joseph Audio Profiles (originally $7k/pr.) for sale here now in your price range, and I'd be shocked if they don't absolutely blow you away.  If they don't you can likely sell them for little or no loss.  

Couple last thoughts -- the Profiles (and many good speakers) appreciate some space between them and the rear wall to sound more balanced and image properly.  Also, these speakers (and virtually all others recommended here) will greatly reward you with a good separate stereo amp and preamp rather than a receiver -- just a thought for down the road a bit, and something to look forward to actually.  Best of luck!