First of all, I don't think those towers will match with your center really well, although I do think it will be closer in sound than non-Klipsch speakers. I would guess it isn't a horrible mismatch, it's probably passable. Also, for whatever reason, the Klipsch Icon series gets bashed a lot by Klipsch afficionados. You can read about that in Klipsch forums and threads all over the place. However, I don't know if it is because they truly do not sound very good, or because their design deviates a bit from Klipsch tradition. Honestly, I suspect it is mostly due to the latter. A lot of these guys own stuff like Klipschorns and Heresy's, speakers that are the size of cabinet dressers, and are sometimes powered by 15 watt tube amps. I'm guessing they are going to have a problem with a slim, self-amplified, aluminum speaker bearing the name 'Klipsch'.
Also, like I said above, note that the XF48 speakers you are talking about are self-amplified speakers, so they won't be using the amplifier section of your receiver. Make sure your receiver has the right pre-outs. If you already have the receiver, you might get something to take better advantage of it. Plus, that price at Vann's is per speaker, not per pair. If I were looking at tower speakers in that price range though, there are other ones I would look at, to be honest.