OP UPDATE:
KRK KNS-8400
Ok guys, SO.... I made my way down to the local Long & McQuade yesterday to see if they had anything I could try on. First, I tried on some KNS8400's by KRK. For the $149 (or close to that) price tag they had hung on them, they sounded great! I found the frequency response to be very flat across the board, and VERY nice to listen to. The lows are not quite as powerful as the M50's, but they are definitely noticeable and I felt a little vibrating in my ears on a few songs
. I also noticed how the highs are extremely well presented, and not harsh on the ears in any way. They kind of roll off in a smooth, enjoyable fashion. I was a little unimpressed with the soundstage on these, but they are closed can so good soundstages are hard to come by. Overall, I appreciated listening to them. They aren't necessarily a "fun" headphone, since they are very flat, but would be tremendous for studio monitoring / mixing, and more mellowed out listeners (which I happen to be most of the time). Especially since you still get those deep lows to give you a little thump. Definitely worth the little money they are worth, and I would say there's a good chance they outperform a few $200+ headphones.
Pioneer HDJ-1500
After these, I tried on a pair of Pioneer HDJ-1500 "DJ headphones". Now these headphones are not over the ear, but in fact on-ear headphones. Personally, I'm not a fan of on-ears because I find them uncomfortable to wear for extended periods of time due to the clamp, and also the fact that you don't really get that 'immersed in the music' feeling that over-ears provide.
But... To the point. As I put the HDJ 1500's on, I really noticed the powerful clamp on them. It almost feels as though they're trying to push through your skull. On the other hand, they ARE meant for DJ'ing and the tight clamp would prevent them from falling off during a crazy head bump session. Sound wise, I found them to be very playful in the mids / highs. Any songs that are very 'busy' with mids and highs are almost unenjoyable with these headphones. The treble is extremely apparent, and the high frequencies are sharp to the ear. The lows wren't too bad, I could feel a little bass, but the progression from low to high was way to bright and excited for me... Back in the box they went.
Beyerdynamic DT-770 32Ohm LE
Third, I made my way over to they Beyerdynamic section
. Unfortunately, they didn't have the DT770 Pro 80's I was interested in... SO instead I decided to try a pair of the 32Ohm Limited Editions. The 32Ohm was both a sign of grief/relief for me. Since I'm going to be using a laptop and an iPhone to power my headphones, the 32Ohm would be very easy to drive. On the other hand, I plan on getting a nice little Fiio in the future, and I feel as though the performance of these headphones with an AMP would only very marginally increase, as compared to the 80's or 250's per say. Alas, I put them on. They are a fairly comfortable can ( a little more than my M50's actually), but the "soft skin" cheap pleathery material they used for the ear muffs (same as the M50's) disappointed me, as I thought they would have been the velour pads. Owell... Sound wise, they were great. After reading reviews on the DT770's, I thought these would have had the overpowered bass of a 'basshead' can, but nope. Not at all. I found the deep bass to be fairly tight and almost exactly where the bass level needed to be. You could feel the vibration on some bass heavy songs, and when listening to more pop / punk music the bass retreated was perfect. All the hype about the recessed mids had me scared to give these a try, but again, nope. Not at all. I found the mids to be even a little more forward than my M50's. It was nice. The only thing I could point out negative sound wise, was the highs. They are indeed sharp and sting a bit when symbols are being hit per say. I guess that's an easy fix with the EQ, but the highs definitely need some working in. The soundstage was a little under what I thought it would be, but it's definitely better than the Audio Technica's. By a mile. Listening to some of my chillstep / atmospheric songs, I could hear the sounds floating around my head, it was great. After a few songs I put these back in the box.
Beyerdynamic DT-770 Pro 250Ohm
As it turned out, they had an opened pair of 770 250's that were sitting in the percussion room to use for drummers testing out the drums. Sweet! After being told my poor little iPhone and laptop would be insufficient in driving these bests, I was wondering how crappy and low volume they would sound. Let's see! I sat down in the drummers chair and plugged em in with an adapter an associate lent to me. WHAT THE ******. I couldn't believe what I was hearing. Not only did my little iPhone push these monsters to a high volume I didn't expect, but they sounded like Jesus was hiding in the cans and was whispering sweet nothings in my ear. Seriously. I took them off a few times to even check. I didn't find him though, so it must of just been the sheer power of these cans. Okay, maybe I'm over-hyping with the whole Jesus bit, but I'm not kidding. I fell in love with these headphones for the next hour and a half I was in that chair. I was amazed by how much more clear and better sounding these cans were than the 32Ohm version. They sounded like two completely different headphones to me. The first thing I noticed was how comfortable they were to wear. The velour pads really feel nice on the head, and my ears perfectly fit in the large cups. They also have a light / moderate clamp, so in combination with the comfy pads you almost forget they are even on your head! I don't know where to begin on the quality of sound. I threw every genre I had at these and every single time I was brought to close my eyes and just.... enjoy. My soft chillstep songs were just wonderful. The lows made a relaxing rumble in my ears, and as they progress up the scale to mid frequencies, the 770's reproduced it beautifully soft and relaxing. I didn't find the mids to be very recessed at all, but more calming and easy to listen to. I was expecting the highs to be sharp and painful like the 32Ohms but to my surprise they were great. Still a TAD too harsh, but nothing I would even begin to complain about, especially when you can just drop the high EQ's a tad. The soundstage on these was also noticeably better than the 32Ohm's. I don't know if it was just a result of me enjoying the overall sound of the headphones more, or if it's actually better. Either way, I was lost in the music when having the 250Ohms on. Just pure blissfulness. Before I left, I decided to mix it up a bit and see how the vocals performed on these. I threw on a FLAC version of Pressure (Acoustic): Live from Q101 Chicago by Paramore. My god. The vocals and acoustic frequencies are just mind blowing. I thought Hayley Williams was right beside me. It was absolutely fantastic. Also, her voice is naturally on the high side of the spectrum, and the 250Ohms didn't hurt my ears whatsoever with the highs.It was perfect.
Anyways, nearly 2 hours and a few impatient drummer customers later, I was out of there with a mission to get rid of these M50's out of my hands ASAP So I can purchase those DT770 Pro 250's. The DT770 Pro 250's outperform by M50's in every possible way. Even in imaginary ways. Even in your dreams. The M50's just aren't in the same universe with the DT770 Pro 250's. Actually, the 770's are on their own planet filled with luscious sounds and beautiful transitions and walk around on their little headphone legs all by themselves with no other kind of headphone occupying the planet. You know why? Because in this $200 price point, nothing else compares. There's my days summary for ya. Hope it helped some of you make a few decisions on which headphones to choose.
(seriously I can only think of HD 201, HD 280, HD 380, and HD-25 off hand (and Mal's post reminded me they also make Momentum, so that's five)). 
but if you like them that much straight out of your iPhone I think that's great because you can only go up from there.