Okay -- just wow. I'm so very impressed with the direction that Games Workshop has been taking recently; ranging from their asking the community for their favourite questions to be FAQ'ed,the release of some very popular armies like gene stealer cults, and NOW: 40k Thousand Sons. Oh my. I think I need to earn more money to cope.
Although I really like the sculpts of all of these pre-releases, especially the Tzaangors, the real favourite for me are the terminators -- these occult elite of the Thousand Sons look awesome. Not only do they feature icons of the old legion and equipment to match, but they're also very clearly based on the Tartaros terminator mark armour from 30k. I can certainly see these miniatures being popular for 40k and 30k alike (with a bit of work for the latter arguably). Just fantastic overall!