Hi.There are much better receivers than the Yamaha .Onkyo,Denon, and NAD make excellent equipment.I dont know how much your budget is but i recommend NAD because of their excellent sound quality.They have never had a bad review as far as i know. The NAD T163 Surround Sound Processor Pre-Amplifier with the NAD T793 7 Channel Power Amplifier is an awsome combination which will give you all you need .Spearit Sound is selling this combination for$1948 with a saving of nearly $1500.You will have the very best at nearly half price. A lot of people will say spend more money on the speakers rather than the amplifier.While that may be true your speakers are going to sound a lot better with an amp. that delivers a clean signal .The Hi.FI. chain starts at the front end and if there is a short cumming it will be exasabated by the speakers. That is why the choice of amplifier is critical to the final output which is the speakers.You can always upgrade to better speakers later on.Changing amps is a lot more expensive. There is a saying in hi fi :"garbage in =garbage out".
If you are going to keep you Klipsch rear channel speakers it is best to use speakers that are made from the same manufacturer to avoid differences in sound quality.If you are not particularly concerned about that then buy the ones that sound best for you .You have to listen because everyone has their own opinion as to what is a better speaker.There are some excellent Klipsch Speakers available at Vann's.
Have a look at the specifications bellow.
http://www.spearitsound.com/nad/nadspec.htm
http://news.ecoustics.com/bbs/messages/10381/163851.htm
http://nadelectronics.com/products/home-theatre-amplifiers/M25-7-Channel-Amplifier/specs
http://www.vanns.com/shop/servlet/category/type/31
http://www.vanns.com/shop/servlet/item/features/540159446
http://www.vanns.com/shop/servlet/item/features/540349076?v_c=GoogleBase
P.S. I live in Australia and i'm not familiar with your stores that sell the equipment. I do have NAD amplifiers and can recommend them soley on their sound quality where other A/Vreceivers fall short.
I hope this will give you an idea on what to buy.
cheers.