I'm partial to the Chevelle, but either one would make a good investment and fun car to own.
But please, whatever yo do, drive it. That's where the fun is. It is a shame to see one in a warehouse, covered up and never driven.
Do lot's of research too. Go to some car shows if you can. If you are buying for an investment, you must do lot's of research to know what you are buying.
Oh yeah, and if you really want a classic get either of these as convertibles.
Good Luck.
www.chevelles.com