Honestly it's pretty hard to say, as both are so different as others have noted. I'd characterize it like this:
The TH900 excels over the W3000ANV in terms of spatial reproduction (imaging, separation, etc.). It has a definite U-shaped coloration, but it's been refined to the point where it sounds great with a wide variety of genres IMHO. Still, not everyone wants a U-shape all the time. Fortunately, those who feel the bass is too emphasized on some tracks can adjust it with EQ easily, as the bass is very clean. Unfortunately, the midrange suckout isn't as easily fixable to my ears, and if one is particularly sensitive to this, then it doesn't matter how refined the TH900 is in other areas. Still, I'd say overall the TH900 is fairly adaptable and more versatile in that it varies more on a track by track basis.
The W3000ANV on the other hand is going to impart more of its unique presence on one's music. Its most apparent coloration is timbrel, the [in]famous Audio-Technica mids. This isn't really something you can EQ away if you don't like. However those who do like it are treated to an experience quite unlike anything any other flagship headphone currently on the market can give. Compared to the TH900, the midrange presentation is better. Its bass has plenty of impact and is tight, textured, and well-controlled (sounds rather lewd... : \ ), but I feel the TH900 trumps it there hands down. I think the TH900 is more refined up top as well. Overall, I think the TH900 is more consistently ahead of the W3000ANV with respect to a wider array of criteria, but the W3000ANV does somethings better and in some respects provides an experience you can't find anywhere else. For better or worse.
So as much as it may sound like a copout, it's really something that depends on one's priorities. For me, the TH900 is the better headphone. I love both however.