l am looking to buy some complete sets of baseball cards, which ones are the best to have from 1980-2008....also, who are some good rookies who will probably be worth something in the future?

a-rod joba chamberlain k-rod maybe derek jater and mariano rivera definitely dave righetti

It really all depends on the year. Do some research and see which players where in that year, especially rookie's.

As for good rokies for the future there is Tim Lincecum, Evan Longoria, B.J Upton, Jacoby Ellsbury, Justin Upton, Troy Tuliwitzki (not sure on the spelling) just the tops young guys in the last few years. And there rookie cards should be cheap also.

If you are buying baseball cards printed after 1960 as an investment, you are seriously misguided. Just a warning.