1- Nice receiver! I'm a big Onkyo fan. (Have one myself)
2 - Ignore what any one tells you. Go listen for yourself. Everyone's ears are different, and they hear things in different ways. So what sounds great to me, might sound dull or muddy to you.
Best thing I can suggest is to go try and find a audio retailer that will let you listen to many different speakers all on the same source (don't have to be Onkyo, but you want to be able to compare apples to apples). Most, if not all good audio retailers will have a sound room just for this purpose.
Now on a personal note, avoid Bose. Unless your buying their high end 901's and have the room for it, Bose's sound reproduction is very in accurate. They look better than they sound.
Also personal likes are JBL (Favorite), Infinity, Polk, Klipsch (can go both good and bad), and some Boston Acoustics. Those are ones you should easily be able to find. There are others, but they start going real high end like Bang & Olufsen... $$$$$$ but SWWWEEEET!
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