H2 has the best music for me, followed by H3. The more quiet music can be listened to for eaons at a time, and Rob and Paul have showed before that they can create exciting and epic music of the more quiet kind without going overboard The epic, grand and big orchestral pieces are great, in fact superb, but listening to them all the time quickly makes them anoying. It shouldn't become too "epic" and "grand" but rather concentrate on creating an atmosphere and telling a story.
There is no real need to base it on one of the former heroes, as long as it in some way keeps the soul of heroes. I would like the future music ot be its own. Although the battle music did get a bit anoying after the 10.000th battle It was pure atmosphere, good music, told a story and was nice and peaceful in an interesting way, which made sure you didn't want to turn it off. Regarding the music, then I think the music of HoMM II Price of Loyalty was the best one. Rob King and Paul Romero have written all the music for all the HoMM games (Paul joined for HoMM II) not knowing their names is herecy and you should be punished by stating 5 times that Rob and Paul are Kings of the musical Rome I think they should get the same person as in HoMM V as he really did a great job.
After all, if we want to influence how HoMM VI is, looks, feels and sounds, then it is now, before the game course is set and decided, that we should make our opinion known. I must admit I'm unsure myself, but I will come with a suggestion or two later on, and hopefully you'll do the same.
Should it be like one of the old game's music, should it keep the HoMM feel but evolve (and what then is the HoMM feel?), or should the developers say that the series has grown up and needs a totally different set of music? And if so, then what should that music be like? Post apocalyptic atmospheric music, symphonic soft metal, more to the classical side, get Klaus Badelt and his themes (he is the one who made the music for Pirates of the Caribbean, Gladiator and such), or should we take Ennio Morricone and his brilliant and story telling music? Which of the old games had the best music is a hard decision (though I would say either HoMM II or its expansion - the games had different sets of music), but an even harder decision is how the future music of HoMM VI should be like. Hearing the Necromancer's theme from HoMM II/III gives you goosebumps and rights away sends you into the game, listening to the Rampart or Sorceress music leaves you with the impression that you are an elf, and the Castle music sends you into a buzzing crowd of humans, where fellowship and "for the Griffin Empire" is everything. Which of these is the most important aspect is hard to decide, but being as I'm still regularly listening to the superb music of Might and Magic VII and VIII on a regular basis and the HoMM I - III music now and then, I would say that for me at least it is the music which leaves the deepest impact. That no game is anything without a good and believable story which drags you into it, a certain look which fits to the game and/or some good music. I'll claim that these only are the fundament of a game. Some claim that it's the game mechanics, the battles, the systems and the factions which create a game.