Every so often I get out my old Rogue Trader Rulebook and leaf happily through it...what a different animal Rogue Trader was from what 40k is now. Rick Priestly essentially gave the fans some historical background and some basic rules, and then said "Now get out there and have fun with it."
Much like Warhammer Fantasy Battle 2nd edition, Rogue Trader is a miniatures game with a strong role-playing element. Telling a good story is at least as important as defeating your enemy. Games are for goofing off, getting creative and having fun. There is little or nothing in the way of tournament rules, but the book gives you all sorts of crazy scenarios you can delve into and get inspired by. I had an opportunity to pick up a bunch of splendid Forces of the Imperium figures last week (more on them later,) and so I've been getting out my old Space Orks and Eldar Harlequins and dusting them off, brooding on writing up some little scenarios for them.
I still like these old school boys, and use them for Trukk Boyz in my new school 40k army on the rare occasions when Dustin and I get a chance to do battle with each other again...(They're small so they fit nicely in the Trukks...)
These days I'm increasingly becoming interested in writing Rogue trader scenarios and mini-campaigns populated purely by old-school figures.