As far as having towers for surrounds and/or rear surrounds, I usually use bookshelf speakers for placement reasons particularly, but recently had a chance to get some towers in the same series as my mains in my primary setup and have the floor space for them for use as surrounds. As long as you can position the speakers appropriately I wouldn't get too worked up over the form factor. I am a little confused if you're talking about surrounds or rear surrounds for the towers, and if anything I'd prefer the towers as surrounds rather than rear surrounds just for content reasons. You might need to put risers underneath them to position them correctly for proper height, too.
As to making a package purchase, have no experience really. I've generally bought piecemeal. You might check out accessories4less.com for avr and speaker sets (but don't think they have Klipsch but not sure). For a Klipsch package deal your local Best Buy might be a good way to go; I wouldn't get the Klipsch subs particularly unless you really like the aesthetics of the copper colored cones....but I'd look to Hsu, SVS, Rythmik etc for subs, if not DIY.