Good home theater speakers to complement my Onkyo?

I just bought an Onkyo TX-SR604/S Home Theater Receiver and am wondering if it makes sense to upgrade my home theater speakers. I’m currently using a set of Sony home theater speakers that I picked up about 4 years ago.

I’m not looking to spend a ton of cash, but figure a speaker upgrade may be needed to get the full value of my Onkyo.

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