I'm using the hd25 for playing dj sets, but not for studio. For DJing they are pretty awesome, i don't regret buying them, they are worth every cent. I haven't really tried out sennheiser studio headphones, i got AKGs and i'm pretty happy with them, because they never lie. If it sounds shitty on them, it simply sounds shitty everywhere. It's only difficult to figure out the sub on headphones.
Has anyone bought the new, colored sennheiser headphones? I think they are neither for DJing, nor for studio? Just for consuming? Anyways, would still be a good reference i guess.