Greetings.
You're on the right track. I really like all the soft synths that you've mentioned. However if you are really interested in traditional or classic keyboard sounds then I have a few suggestions.
My favorite software instrument for Rhodes sounds (and all kinds of electric pianos too) is Applied Acoustics "Lounge Lizard".

For Organ sounds on the other hand I would recommend Native Instruments B4 or USB "Charlie". Both are great. B4 is based on physical modeling of the actual B3/C3 Hammond organs. Charlie on the other hand is basically a sample playback instrument that comes loaded with actual samples of a Hammond B3 and C3 organs. I think that both are great and fantastic to work with. I prefer using "Charlie" because the sounds seem to work better in the mix.

Being Logic 7 user I actually have access to quite a few really powerful soft synths that model Rhodes, Clavinets, Organs etc. BUt you can only use those if you have Logic 7 Pro as they are built in right into the program.

-ED-