Multiple choice - both Pathfinder and Fantasy Craft are on my 'must buy' list. However, it is likely that I will continue to use E.N. Publishing's Elements of Magic: Mythic Earth as my spell system of choice (I currently use it for my Steampunk/Spycraft game)
I also like True 20 when I need a quick 'generic' game engine.
4th ed. is not one of my choices... the more I look at it the less I like it, so no go. (And I am actually have the mildest dislike for 4e in my group.  )
The Auld Grump
__________________ Oh, I am a cook, and a captain bold, and the mate of the Nancy brig,
The midship mite,
And the Bo'sun tight,
And the crew of the captain's gig... |