Obviously lots of strong opinions on this...

Personally, I'd highly recommend the Grand Hyatt in Roppongi. For expats in Japan, Roppongi may feel something reminiscent to America, but trust me, for those visiting - even for me coming every 4-8 weeks - it still very much feels like Japan.

The reason I'd suggest is is that I've personally found it to be a good starting point for touring the city via subway to places like Ginza, Tsukiji, Akihabara, Harajuku and many of the parks / other sites. It may not be the most centrally located, nor is it the best hotel in the city, but it's pretty damn nice, especially on the club level, and if you are in any way inclined to nightlife and people watching, it's a fantastic base in the heart of Roppongi.

I also like easy accessibility to Roppongi Hills and the Mori Art Museum and Tokyo City View on the top of the Mori building. All excellent sites IMHO, and literally in the same structure as the hotel.

Anyways... I don't think any of the advice above is 'bad'. I think most folks would be happy with any of these options.