Pride's actually defunct now (got bought by the UFC a year or two back).
The big two Japanese Orgs are Dream (run by a combination of ex-Pride staff and FEG who replaced their Romanax/Hero series with it) and Sengoku, both of which are solid orgs.
K1 itself is just doing kickboxing now (although as said above, FEG helps run Dream)
However, personal favourites are the smaller ones: Deep, Pancrase, SHOOTO and ZST (which is probably my favourite org ever).
Outside of that, as a Brit I'm obviously a big fan of the UK orgs and there's a lot of quality European mma out there.