if you buy new, I would go for the 2080 mainly for resale values. There isn't much future proofing with ray tracing, those cards will be obsolete by the time that takes off (they peformance was shown to be awful in the Nvidia keynote). If anything, an argument could be made for the 11gb of video memory that a 1080ti for fute proofing. But to be honest the rtx 2080 does just fine anyways. If you can buy a used 1080ti, then i would jump on those. I got my 1080ti for close to 450USD for example