Does anybody think that Harmonix will ever go back to these series, when they've been preoccupied with these peripheral based games for the past five years? I can't be statisfied trying to play Guitar Hero with my 360 controller. *sighs* I miss Amplitude...

Unfortunately, i really don't think so..  I mean, that is to say that Guitar Hero isn't the spiritual successor to the Frequency/Amplitude series. Although they are by no means the same game, to anyone who has played both games can attest to the fact that many of the main game play functions were adapted to fit the game play of the first Guitar Hero. But as a whole, the rhythm game genre is has reached a point where the standard is to either have some sort of gimmick or peripheral. Right now it just doesn't seem like there is much of a market for a straight forward music game such as this series. Has the time for that style of game passed? Who really knows? But i wouldn't hold my breath..

Well there's 'Phase', which completes the 'Harmonix music games with titles based on spectral phenomena and only three notes' trilogy.  Personally, though, I like their later games a lot better.  Certainly there's a lot that can be stretched out of 'controller as musical instrument' games, but Harmonix decided to go in a different direction, fixing the controller rather than trying to shoehorn more complicated gameplay into it.  I'd certainly be interested if they decided to go back to more dance-themed music, but in all other ways, gamplay-wise, I think their newer games are superior. 

-N

I really think guitar hero/rock band was the direction they wanted to go with the serious. I think its a step forward, but i'll always love amplitude

I dont know, good question. I think it would make a good DS game. I would really enjoy a new one

I always wished that they would have continued to make games in the same vein, but as I've played more of Guitar Hero and Rock Band I've realized that it's really the way to go. Amplitude is a good enough game to this day to fill all my scrolling along a track mashing L1 R1 and R2 needs

I think it'd be cool if they made another one. I wouldn't count on it though.

I really would like one but ehh I think theyre workin on Rock Band 2 and such

Probably not, but you may see Amplitude on PSP or something at some point.