2000 Monte SS Shocks

Well as of recently I've been feeling more vibrations as I drive and after coming off a speed bump the back bounces more. These are still the stock ones and the ol' girl is getting up there, she'll be 7 on the 6th of April, so I'm guess it might be around time to get some new ones. She's got 70700+ miles right now.

Anything I should know about getting new shocks? Should I go aftermarket or back with the OEM ones? Should I look into struts too? I'm open to all advice, I don't know much about suspensions.

Well I guess that shows how ignorant I am about suspensions. I guess my car doesn't have shocks, just struts. So same questions just about struts.