Followers may recall I own some capital blueprints, which I make copies of to sell.
A year ago supercarrier blueprints were where it was at, but now it looks like we've reached something of a denouement in that market as they've all fallen below a billion isk (their pre-dominion value) except for the wyvern. A year ago nyx BPC were going for 3.3 billion; today they're 790 million. Interestingly the wyvern is the most expensive supercarrier BPC, with an MMPB (millions of isk per month per billion isk invested) of 27; I expect this is because with nyx and aeon being the only supercarriers actually worth flying few people invested in wyvern BPO, while a lot of people are caldari specced.
In the rest of the BPC market pretty much the only thing worth investing in are archon and thanatos blueprints (currently 40 MMPB), whose BPC have been fairly consistently worth more than chimera and nidhoggur BPC (currently 23 MMPB). The only other sub-supercapital with more than 25 MMPB is the orca, and that won't last.
If you have the cash titans are looking pretty good, and demand actually looks to have increased a bit. Leviathan BPC are over 3 billion for the first time, like, ever, and the other three are sitting at 8-10 billion, which is 22-27 MMPB. Avatar and erebus are probably the best investment opportunities; ragnaroks die more, which in theory could increase demand but more likely will make people stop flying them, while the avatar has the highest EHP and erebi are necessary for armor bonuses.