Shigeru Joshima （城島茂） lead guitar
Taichi Kokubun （国分太一） keyboards
Tatsuya Yamaguchi （山口達也） bass
Masahiro Matsuoka （松岡昌宏） drums
Tomoya Nagase （長瀬智也） rhythm guitar
I'm no expert on the Johnny's groups, but I think TOKIO is the one band in the harem that actually handles musical instruments on a regular basis. Although I've seen the 5 guys regularly on the variety shows and even in some of the dramas, I only know a couple of their songs off the top of my head. One was their 3rd single, the 1995 "Uwasa no Kiss"（うわさのキッス） which was the theme for an anime, "Kiteretsu no Daihyakka"（キテレツの大百科）. And then there was their 28th single, "Ambitious Japan", released in October 2003.
The song found its genesis from the then-president (now chairman) of railroad company JR Tokai, Yoshiyuki Kasai（葛西敬之）, when he approached veteran lyricist, Rei Nakanishi（なかにし礼）, and asked him to write a railroad song to coincide with the opening of Tokyo's Shinagawa Station's new area to handle the Shinkansen (Bullet Trains). The song and its title were used as part of the big campaign, with the Bullets' 300 and 700-series trains emblazoned with "AMBITIOUS JAPAN". I even remember seeing the huge posters of the well-suited members of TOKIO adorning the pillars in Shinagawa Station.
b_macd from Flickr