I have to challenge all of these calls for 'neutral', as to me, 'neutral' is an ambiguous reference. However, many times on these boards, 'neutral' is used to refer to gear that is 'transparent', or gear that artificially brightens the upper midrange and lower treble region.
In my opinion, I also like a 'neutral' sound, a sound that is not rolled off, or darkened, but also a sound that is not artificially highlighted, or lightened. Many times I listen to equipment that some folk refer to as 'neutral', and it is obvious that the equipment has emphasis in the 'presence' range, to help highlight detail. In my humble opinion, this is NOT neutral.
I have nothing against folks that enjoy a tilted up high frequency response, but I do wish they would stop referring to it as 'neutral' sounding. Neutral gear should sound neither rolled off nor lit up, it should just sound relaxed and natural.