Well, that's why I prefaced with "*one* classic exotic car" - I know that neither the Daytona nor anything else from 1970 can compare to a modern supercar - but what else is there that more perfectly defines the classic beauty of the extreme performance European sports car from the 60s & 70s other than the Daytona & Miura?? Maybe an Aston - but I don't think the 60s & 70s Astons can match the beautiful bodywork of the Italians.
Now, the real question is: Are any of the late 60s & early 70s supercars worth driving. I think so - but not in the same way as a modern supercar - but in a way that honors the car for what it represents in history, the influence it had on later cars and to experience the best that brilliant engineering & design in 1970 could produce. That certainly seems worthwhile to me!
Well, if you want domestic, it's hard to argue with a nice `70 Hemi `cuda or `68 Shelby Mustang. There's also the L88 `67 Stingray and Shelby Cobras and Daytonas, of course, if you have deeper pockets. In Italians, I don't think the 365 GTB/4 is worth regular retail, there's an awful lot of them. At some point the market for them will rebound, but it's not soon. The 275 GTB is a star, and it's rising, look for values on those to double in the next 24 months, now that people are realizing how scarce they truly are (and how gorgeous). Also the "off" 250s, Ellena and Boano models, are becoming more rare, as people chop them to pieces to build Cali, GTO, and TdF knockoffs. Hard to go wrong with them, given today's pricing, if you can find one. That's a late-`50s Prancer, on the cheap (comparatively).
So, yeah, 275 GTB of any stripe, preferably alloy, that's what I recommend if you can only have one classic, exotic beauty.