My solution is to use a variety of external hard drives, with a few flash drives. I only ever buy USB-powered hard drives these days, my favourite being the WD "my Passport" series, as they're not vulnerable to fluctuating or failing mains power. I've had mains-powered external hard drives destroyed by power surges in 3rd world countries (like here). I currently have 5 or 6 of these, up to 3/4tb, with a couple of 1tb ones on the way. Everything is on at least two separate drives, and I keep them softly packaged in two different places.
I have a few 32gb USB flash drives, but the problem with those is that I've never found a way to format them NTFS, so 4gb is the largest file I can put on them. Fine for photographs of course, until Canon brings out its first 1000mp camera (!), but no good for what I originally bought them for which was to store ISO video images.
Obviously I have to carry a computer as well, but as I always do that's no hardship.
5D & 7D (both gripped), 24-105L, 100-400L, 15-85, 50 f1.8, Tamron 28-75, Sigma 12-24, G10, EX-Z55 & U/W housing, A1+10 lenses, tripods, lighting gear, etc. etc.
"I prefer radio to television. The pictures are better"