I'm not going this year but, I went last year and had a blast. I didn't go to japan specifically for the game show but it was a part of our tour. At the time I didn't have any of the nextgen consoles so the show wasn't the main focus of the tour for me.
The day we went it was packed, epically around the MSG4 and DMC4 booths. I only got the chance to play a couple of games though (I'm not a big fan of waiting in line).
I'd say it is definitely worth the visit to see all the cool games that will never come out anywhere but Japan.
TGS '07 - a set on Flickr
TGS '07 Booth Babes - a set on Flickr