I believe that one vendor said that, the more money you invest in a pair of headphones, the more subtle the differences. According to Skylab, whose opinions deserve careful consideration, it may be coin flip between the HD800 and T1. Considering the write-ups, it seems that the three headphones are neck in neck on several criteria.
As mentioned, comfort is important; for me, it's best to have headphones you can wear for extended periods of time, and I'm not convinced that any of the three phones better the the DT880. The T1 is said to be roughly equal to the HD800 on several levels, considering your preferences in music and sound. My rhetorical question is this: as a HD800 owner, is it worth it to invest the LCD-2 and/T1? Obviously, a few people in this forum feel it is. I'm glad to have their feedback. But would it be worthwhile to spend around $1000 more on a headphone for a slight difference/improvement in sound?