Hmm, 136GB due to ecchi doujins/manga (not including the non-ecchi doujins). I am actually picky and don't download the vast vast majority of stuff I come across. The doujins/manga far outweigh the video hentai of which I actually have very little of. As for doujins, I only have a tiny fraction of what is actually out there. I have crossed paths with petabytes of hentai over all these years on the internet. That is not counting the real doujins/manga/DVD I have on the shelves. I have several thousand dollars of ecchi/hentai print media plus some purchased video discs collected over the years of travelling to japan or buying from import services and online import agents. I don't buy from jlist as they are one of the highest priced places to get a quantity purchase from (and I also regard its owner as dishonest).
For those looking to easily amass large collections, if you go to
BAKABT.COM and download all of their hentai/ecchi manga/artbooks/video, you'd have over a terabyte. Really, their hentai category is really huge and well-seeded. Since
bakabt.com doesn't carry doujins, you would then go to deadfrog for the older torrents and to nyaatorrents for the more recent ones. Unlike
bakabt.com however, both nyaa/deadfrog have problems keeping older torrents seeded.
http://www.bakabt.comhttp://www.deadfrog.us/http://www.nyaatorrents.org/http://www.tokyotosho.info/If you buy videos online, use the dvdepricesearch metasearch engine to find the lowest price online. It scans the various major dvd sellers every day to build up its database of prices.
http://www.dvdpricesearch.com/ Thankfully, Tsukiumi allows me to collect this kind of stuff.