I'm about to purchase my first pair of quality headphones, and spending a lot of time reading through head-fi and some external reviews and almost drowning in uncertainty, I think I've finally narrowed my decision down.

My taste in music is quite eclectic. I listen to Jazz, Classical, Death Metal, Prog Rock/Metal, IDM, Folk, Pop and whatever else I come across that sounds good. Therefore I feel something fairly well-rounded/balanced is in order. I don't want smatterings of bass; as long as it's present I'm fine. Because of that, these are the headphones I've narrowed things down to:

Beta Brainwavz Pro
ER6i
RE0

So, first question: is the jump from the Brainwavz up to the other two significant? That is to say, as somebody who has never used a proper headphone before, would I be likely to identify a difference in SQ if I picked up the Brainwavz and compared it to the other two? Bit of a convoluted question, and probably highly difficult to answer, but I'm just to trying to justifying spending the extra money when I'm not certain if I will notice it without prior experience.

Also, if I went for either the ER6i or the RE0, is the RE0 worth the little extra? As a first-timer I'm not sure it will be, unless it comes down to build quality or general consensus on ease of fit. Noise attenuation isn't a deciding factor.

I started off liking the "sound" of the RE0 and (after going through every sub-$100 headphone I could find) it's still there, and yet since I found I could get the ER6i for a far cheaper price than where I first saw them, I'm leaning towards that. Is there any good reason I shouldn't get the ER6i over the RE0 (assuming I should get either over the Brainwavz)?

Finally (this is getting long, sorry), I will be using these headphones with a Cowon S9 PMP, and it will be used UNamped - at least initially.

Any help in making my decision easier would be appreciated, thanks. Although if there's something that fits my needs better for a similar (or less) price, I'm all ears (excuse the pun ). Thanks!

(man, I've used a lot of parentheses in this post)

EDIT: Maybe the Altec Lansing iM716 could be thrown in here too?

well ive only heard the beta's but from the reviews of the RE-0 ive read and what they get compared to for $100 are the bargain buy just now.

IMO the Er6i are not ideal for Death/Metal and other heavy rock genres. I'd take the RE0 over the other two if you can afford it.

Yeah, I'd go RE0 as well.