I'll add a specific entry for Takesaki's books. I learnt what von Neumann theory I know from these books. Especially volume 2 is a very nice, and concise, guide to an awful lot of the theory around Tomita-Takesaki and Connes' theory of weights.
If you are interested in Tomita-Takesaki, in a gentler fashion, then the old books by Stratila are nice. In particular, they explain the unbounded operator theory somewhat more than Takesaki does.
But it really depends what the original interest is: if you want to get into modern C*-algebra theory, then Takesaki is not the way to go.
Finally, for reference, the recent book by Blakadar is wonderful, and is a great place to look for something, before reading up in more detail somewhere else.
