another selection of closed headphone at this price will be audio technica ath-a900x, philips fidelio (seems nice)
but my choice will stick to mdr-1r (already own it). the ear cup pressure point very comfortable

Sony mdr-1r mk2?

What kind of sound signature do you prefer?
If portable, this price range can consider AKG K550 and ATH M50 too.
If you have an amp, can try AKG K271 mk2. It has very very good potential if pairing with an amp.
Many people won't use a good amp to drive K271 because its prices are quite cheap. But k271 will really impress you if you use an amp to release its potential. The treble and mid are very sweet and lively.

I've tried both big cans above (MDR-1r, K550, M50, K271, DT770...). My favourite is the cheapest K271. haha.

ATH M50x, the newer version of M50, biggest highlight is the detachable cord. It goes for 650rm.
The MDR-1R for some reason didn't impress me at all compared to its price range... Neither did it's MDR siblings. I am a sony fan, but just didn't feel good enough.

the M50 are quite good, but mids are recessed and a little bump in the bass region, however the sound is still quite smooth but highs might be a bit piercing for some people, pads are not really comfortable at least for me
for the price it's really a good deal, change a pair of pads and you're good to go 

Erm...It's quite difficult to definte what is "balance". haha.
In my opinion, Most of the Sennheiser, AKG, Beyerdynamic...etc headphone are balance sound. They just use different ways to show it.
Many sound enginners use them as a monitoring headphone too.

Besides, the sound signature of headphone will influence by whole hifi/headfi system. Even the quality of electrical source will influence the sound. For example, HD800 will sound very weird and unbalance if you connect it with a cell phone. 

Actually most of the sound signature of computer or mobile phone are very "unbalance". It's quite difficult to find a balance, neutral, accurate sound if you use them as a music source.

I've compare K271, MDR-1r and K550 at the same time. Music source is Fiio X3 and Sony PCM-D50.
I don't like K550. The connection between treble, mid and bass is not natural enough. Treble and bass are not bad, and I feel that the mid is very empty, like there is a big hole between treble and bass. haha.
MDR-1r is better than K550, the connection between treble and bass is smoother. If you dun't have an amp, I think MDR-1R is already good enough. It's quite easier to drive.
But compare to K271, I feel MDR-1R is not clear enough. Treble is a little bit blur. The sound of K271 is very clear and refined. I love the sweet treble and mid. Bass is not more than Sennheiser or Beyerdynamic, but more than K6XX/K7xx series. Considering it is a close-back headhone, its sound stage is very wide, but still can't compare to HD600/HD650, K612/712 or Beyer 880/990...