Hi I want to buy home theater surround sound speakers. If there anything that I should know?

Hi I was thinking buying home theater surround sound speakers at Bestbuy. I am only thinking spending 0 or less & maybe Bose it is a good choice. Ok is there anything that I should I know before I buy one? Example, like warranty,HDMI port,supports True HD Sound or DTS? Thank you.
Yes I do need Audio receiver & 5 or 7 speakers.

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