Hey Steve! I have owned both Klipsch and Axiom. Although not ideal, you can mix and match Klipsch with Axiom, but you will have very different sound signatures. At the very least I would make the front three speakers the same. Also, some level matching will be necessary as the Klipsch horns are very easy to drive.
My advice is to order a pair of Axiom Architectural series speakers and do a comparison with the Klipschs. Like I said, there is a very different presentation of sound bewteen horns and domes--one that you need to decide which you like best. If you like the Axioms, then you can still use the RB35s until you save up for the rest of the set.
Better yet, like Randy said, check the audition thread and see if someone is local in your area. Maybe you can take your Klipsch speakers over for a comparison.
