I'm a big fan of the monster packs idea, but on the PC side of things I'm a fair bit more leery.
From a DMs point of view, where does this leave me mini-wise when I want to run evil members of PC races as bad guys? My campaign so far has had bad guy human rogues, a torturer, samurai, ninjas, swashbucklers, pirates of three different varieties, female dwarf clerics, bards, half-orc barbarians, and monks. Are there going to be generic 'bad guy' humans etc in the monster manual packs, or will the only minis of PC races be in the Heroes line? Hopefully the latter (there are 'human berserker' etc entries in the MM afer all), because otherwise it'd be damn near impossible to populate a large encounter with evil human minions etc without buying a dozen PC packs...