What kind of sound are you going for? What kind of money do you want to invest? These are the starting point for all stereos. I personally like alpine speakers, they sound good, are reliable, and don't break the bank. If I was going all prodigal, then I would spring for some high end MB Quartz or some JL speakers sound good...now if you're talking subs, then I am in love with the RE Audio SEX10, they sound beautiful, and hit hard, which I go for sound quality, sql, not sound pressure, spl.
enter in your vehicle info it will tell you what you need. They have mounting kits and good instructions. Done two vehicles through them an explorer and a dakota no problems. Both of them with mostly stuff at the lower price range. Still very happy compared to stock.