~$300 budget for Blu-ray (and light gaming) headphones

That budget doesn't include the amp/DAC/etc. I'd need for it (which, if possible, I'd like recommendations for too, please).

Anyway, my two biggest requirements are that they leak as little sound as possible, and that they're comfortable to wear for 4+ hours. My current headphones, Sony MDR-V600, meet both requirements, and are fine for the music I listen to, but I'd prefer something better particularly for Blu-rays.

I'll be using a laptop, too, so PCI/PCIe sound cards aren't an option, and I'd prefer the amps/DACs/etc. to be USB-powered.

The Beyer 770 Pro seems to be especially comfortable for long use - am I right in that assumption?

On the other hand, the Ultrasone 900 looks to be really high-quality, and the "surround" denotation makes it really appealing (I'd love the best virtual surround sound I could get) - but they seem like headphones that would need an expensive amp or DAC to use properly; would a uDAC-2 be sufficient in either case? If not, is there a good portable amp (or a combo amp/DAC) I could use with either headphones? I was looking at the HeadAmp pico USB DAC/Amp, although at the $500 pricetag, I don't know if it's overkill for the headphones I'm looking at.

I guess I could stretch my headphone and amp/DAC combined budget to $1000, if that make a difference.