I didn't write a very descriptive post, did I? Sighs. M&M was made (I think) by Julian Gollop, the guy behind the original XCOM games. It was as much RTS as RPG, but the blend was handled much better than say Warlords Battlecry (I only played the third) or Warcraft three.
The RPGness was mostly limited to the solo mode, where each mission would give you experience and often items to develop your character. 'Customisable' was a bad choice of word; it offered a lot of options for preparing your character for battle, though there wasn't much in the way of developing a distinctive character.
The spellcasting system was great, though - part of your character development involved buying talismans, of which there were three types: order, chaos and neutral. The most important items in the game were magic ingredients which, before battle, you could place into any free talisman spot (and swap them at will in subsequent missions). Each item would have a different, but somewhat related effect in each talisman type.
About half the items were summoning focused, giving you an increasingly powerful menagerie of (mostly typical fantasy) creatures, running through the spectrum from lowly zombies and brownies to fire(ball) breathing dragons.
The other half were spells. Although you needed creatures to control mana sources, this meant that a fully juiced up wizard was never likely to be overwhelmed by creatures alone, as in some RPG/strat hybrids - he might have a spell that would instantly obliterate two thirds of any enemy force, or one that would force them all to attack one of their friends ignoring all else.
The main problem with the gameplay was that some spells (eg. order/brimstone = cure) were so essential to survival that you never got to use some entertaining alternatives (eg. chaos/brimstone = raise dead). It's a shame the game wasn't more successful, since a patch or two could easily have sorted this out. But even with that problem, there was a lot of scope for experimenting with combinations. One of my favourites was to summon a plague totem (a fixture which inflicts slow damage on anything living near it) and a few lowly undead critters (who could carry and spread plague, but not suffer from it), and walk them into the middle of an enemy army - the plague would jump straight to all the creatures that swarmed in to kill them, and as soon as one of them recovered from it, his neighbours would afflict him with it again.
I never got to play multiplayer, sadly. I suspect it would've required using some of the less obviously useful spells to counter the specific tactics you expect your opponent to use. For example, by far the most powerful (and expensive) creature was the (inspiringly named) Champion of Chaos. Being undead it got a hefty combat bonus vs its order counterpart (the Champion of Order, duh
) despite having less life. But being undead made it almost worthless if the enemy wizard had the Bury Dead spell and was willing to use it - he could dispel the CC for about a fifth of the mana needed to summon it.
Anyway, it's left surprisingly small an impression on the web - it doesn't even have a Wikipedia article, which is a shame. It deserved a cult following at least. And I've always wondered whether the spell combinations I developed were ubiquitous or whether or players would have gone down completely different paths...