[Goride]

Preface:
 
Hi, I'm a student on a budget and I need some advice.  (Note:  because I think it might be relevant here, I am slightly deaf.  For the most part I can hear ok, but do have trouble hearing high frequencies).
 
I have recently ordered:
Sennheiser HD595 ($130)
Sennheiser HD555 ($48)
Astro Mixamp ($130)
FiiO E5 ($18)
 
I was looking for some headphones to listen to music (mainly indie rock, acoustic, metal, prog rock, but other general genres as well), quite a bit of gaming, and maybe a little bit of movie watching.  I've had some experience with Sennheiser PC155 used for gaming and music, and I've enjoyed them.  After a lot of research I decided on the Sennheiser HD595 due to its supposed natural sound, great soundstage (important for games).  I ended up getting the HD555 as well because I found an excellent deal on it.  I saw there was an easy mod to try (haven't done it yet), and figured I could return the HD595 if it really worked.  I went with the Astro Mixamp because I definitely wanted to use it for gaming, and I heard this was probably the best way to do it.  Also, the HD555/595 were only 50Ohms and easy to drive.  So it seemed perfect.
 
So far, I have ONLY been able to test them out using my Macbook Pro and the FiiO E5.  (the mixamp hasn't come in yet).  While the HD595 is more comfortable, and I can detect a little more clarity, it is really hard to tell the difference between the HD555 (unmodded) and the HD595.  However, I am just using the soundcard in my Macbook Pro and the FiiO E5 amp.  Perhaps, the source and amp just aren't enough to really tell.  I've heard that the HD595 takes more advantage of a DAC/AMP than the HD555 does.  I suppose I'll be able to test that out when the Mixamp comes in.  But I'm thinking the difference is still going to be very slight.
 
With all that prefaced, on to the point:
 
I'm thinking I should simply keep the HD555 and return the HD595.  I have already budgeted that $130 for headphones, and I could go up to $150 at max.  I'm thinking of keeping the HD555 and designate that as my gaming headphones, and for when I want a more accurate or relaxing listening experience.  However, I am a little underwhelmed by the bass and "rocking out" ability of them.  For instance, I was listening to some .flac Tool songs and I just couldn't get into that "rocking out feeling" with the Sennheisers.  I wouldn't consider myself a bass-head, but I would like to have a pair of headphones for when I just want some fun rocking out type of listening; where you can really feel and get into the music.
 
I've been trying to do my research and I've found the Grado SR80i, SR125i; Audio Technica ATH-M50, A700; and Shure SRH 440 Pro.  Which all seem to be in my price range.  (I even found a good deal on new Beyer DT770Pro and Beyer DT990Pro for $150 each, but at 250Ohms I'm unsure if the Astro Mixamp + FiiO E5 would be enough to drive them.  Would it?).
 
Any ideas on headphones that would compliment the Sennheisers as a 1-2 punch?  Or do you think once i have the Mixamp, and using it as a DAC, do you think the sound will improve to the point that maybe I don't really need another pair of headphones?

 

[ZARIM]

You can buy 32ohm DT990 for better loud volume through E5 and if 250ohm needed then buy better AMPs like E9+E7.

 

[JoetheArachnid]

Having recently bought a pair of MS-1s to complement my HD 595s, I'd say that Grados are a good accompaniment. I wouldn't write out the Senns entirely for rock though - through my amp I tend to find that the Senns make the better-recorded stuff sound better whilst Grados/Alessandros really shine on some grungier stuff.
 
If you're in the US I'd say go for an SR80/125i for a bigger divergence from the Senns. I tried the SR80i for a weekend and really liked them, but went for the MS-1s because of the vast markup for proper Grados in Europe. (SR80i = $175, MS-1 = $100 with free shipping)