190E 2.3 EVO, or anything else from the 80's before the prices go nuts.
What is your price and goals? You can buy absolutely fantastic SL500's for mid teens.
If you can spend $50k or $60k the 355 Ferrari's are fantastic buys right now. They are the last low production F car before they started spitting them out like crazy. I suspect in 10 years their will be a 1,2, or 3 in front of that $60k.
Remember 10 years ago you could buy a nice Lamborghini Countach for way under $100k, I saw some for $80k all day long. Now good luck finding one under $300k. Low production 80's stuff is going to go nuts in value the way 60's cars did.
No reason you can't buy a fun toy car that might appreciate a bit at the same time!
80's 911's, V12 Jag's, anything rare Mercedes, and M BMW's are going to be solid buys going forward, my generation is just getting to the point where they have money to collect cars.