Pox64,
I fully understand how wires can be an issue. Especially in areas of traffic or where you want to be a little discreet. Just decide for yourself if the trade-off of permanently allocating part of your purchase budget towards a wireless antenna, cheap built-in DAC, cheap built-in amp, cheap built-in battery, and the weight of those components is worth the wireless convenience. I'm going to assume based on your Bluetooth mod on your Senn HD 25-II that you have the modding skills to replace the headset's batteries when they no longer hold a charge. I personally have no idea how the wireless Sony headset you mentioned sounds, Sony makes pretty good products, but I wouldn't believe it sounds better than my Q701 wired into a decent amp/receiver. The Q701 also comes with two long lengths of detachable cable, so I have no problem lounging on a couch while the cable is routed mostly out of the way. IMO, the inexpensive flagship AKG headphone would be the clear all-around choice among those listed for my tastes, especially considering you already own a pair of wireless headphones. I can't tell you if they'll fit your preference for sound signature, but technically they are very capable and high-performing headphones.