Advice on High End Card purchase

[Canofcorn]

Dont you just hate the new guys that always want to "invest" in the cards. Actually, I really do love the hobby aspect...and I've been on the boards for a while now and really enjoyed it. Have done some nice transactions with many of you and built up a nice little collection and have assembled a smattering of 50's-60's rookies...but now it's time to step it up a notch.

In your opinion, what are some card(s) I need to collect that potentially has the best upside in 5-10+ years. Like the 1952 Topps Mantle, if you got a nice one even just a few years ago you are just sitting pretty.

I would like to hear what you guys think. I just want to put myself in the best position. Nothing is guaranteed of course..but I love vintage and it's very stable.
I heard things from, buy a 1951 Bowman Mantle, Goudey Ruth, to a PSA 7 Hank Aaron rookie, to key T206...."nothing sells in a pinch like a Mantle or a Ruth" Is there something else I should keep an eye out for. Budget is up to $5k. It's nothing crazy...but a lot for me. I blame Mike Trout...if he wasn't so good I wouldn't have this Paypal avaialble.

I put this in the baseball section but certainly open to other sports suggestion. (I have a Gretzky O Pee Chee and Jordan already)