We are using Art Magic and I am really falling in love with it.
I was wondering if Art Magic was best used as the only form of magic in the world or if Death Magic, Enchanting and Summoning could be out there somewhere in the mix, in faraway exotic lands or as lost arcane arts jealously guarded by a few secretive, ancient bastards.
We’ve got 'em all in our THAC0 campaign. You can mix and match, but I recommend just two or three at max. Death Art and Art Magic go well together because they’re so far removed in power.
The only thing I wouldn’t mix without careful thought is the base Sorcery rules from BWG and Art Magic. Practical Magic goes well with any high-magic setting. Art Magic is flexible enough that it can easily make your mages too easily able to deal with any situation, but as players and GM are aware and okay with it it goes great. The other arts are niche enough that you can add any or all of them to just about anything—they don’t recreate the kind of sorcery or magery we usually think of from RPGs, both tabletop and electronic, thanks to Gygaxian magic users.
You know, it occurs to me that it would be fascinating to use Vancian magic in BW. Real Vancian magic—the most potent and expert mages get maybe four spells at a time. This really makes use of magic a matter of careful planning and agonizing resource decisions. And simple, too: come up with a spell description and let characters fill their allotted slots. You could even give everyone a slot or two, which can be refilled whenever they have time and access to their books and laboratories. (And none of that Rhialto sandestin cheating!)