AT has you covered on the Lucky Man sound.
As for the Deep Purple sound, I do basically what Jon did.
Run the organ through an amp.
I'll start with a basic organ patch, and insert an amp sim in the FX bin. A preset with a thicker sound seems most effective. Some of the thinner presets intended for lead not so much.
Some examples:
This one is really dirty, maybe more than you are looking for.
http://soundclick.com/share.cfm?id=5915248 Nice and fat, with plenty of overdrive, but not quite as dirty as Moonlight.
http://soundclick.com/share.cfm?id=7528228 This one is experimental, and kind of out there. It is barely recognizable as an organ, and relies heavily on the amp sim.
http://soundclick.com/share.cfm?id=7528228 None of these is an attempt to replicate the DP sound, but maybe it gives you some ideas.