I agree with the "you can't wait forever" aspect. I do own a Kindle 1, bought a DVD player in 1998. A Blu Ray player in 2008 (waited for the format war to end) etc. So I do early adopt.
On this front it's just a case of something I don't need/want that bad. Paper printouts work fine for me and don't cost me a dime so I have little incentive to pay big bucks to early adopt something like the DR that isn't ideal for my needs, just to read and mark up a handful of PDFs a month.
If I was reading and marking up a hundred articles a month or something I'd be more pressed to adopt something. But now it's probably 1-5 on average a month since I've read most everything in my niche now and avoid branching out in my research too much a it's good to stay focused and I don't want to have to become an expert on a new area as I hate reading academic stuff.
It may well be the case that I never buy any tablet device, as they may never fit my needs or budget, and I may stick with printouts and paper books for my academic work. Time will tell. I'm just no in a hurry.
I'm not being confrontational at all, just explaining why I'm not interest in dropping $800+ on technology that I don't really need or want that much.
I'm more interested in a tablet that's not Windows based for couch web browsing, torrenting, etc. without much risk of viruses as I only have a work laptop so I stay away from random web browsing after having problems with trojans and malware.
So if nothing comes along that fits what I'm looking for in a multi-media tablet device, I may say the hell with the tablet and just shell out for a Macbook for those purposes and stick with paper for my academic reading.