Styx

From Lastfm:

Styx is an American rock band, and the first musical act to ever have four consecutive triple platinum albums.

The group originally formed in the Chicago, Illinois, area in 1961 as "The Tradewinds". This earliest line-up of the group included vocalist, pianist, keyboardist, and accordion player Dennis DeYoung, and a rhythm section comprising brothers Chuck Panozzo and John Panozzo on bass and drums, respectively. Changing their name briefly to "TW4", the band added guitarists/vocalists James Young (J.Y.) and John Curulewski. The band members decided to choose a new name when they signed to Wooden Nickel Records; several suggestions were made and, says DeYoung, Styx was chosen because it was "the only one that none of us hated."

Guitarist Tommy Shaw joined the group in 1975 following the departure of Curelewski. Tommy Shaw left in 1983 and returned again in 1995.

Glen Burtnik played guitar, vocals in 90/91 and bass guitar, vocals from 1999 to 2004.

Dennis DeYoung was removed from the band due to a viral ailment that left him sensitive to light in 1999 and was replaced with Lawrence Gowan-Keyboards, Vocals

The present lineup includes new members Todd Sucherman drums, percussion, Lawrence Gowan vocals, keyboards, guitar and Ricky Phillips bass guitar, vocals.

From Wikipedia:

Styx is an American rock band that became famous for its albums from the late 1970s and early 1980s. The Chicago band is known for melding the style of prog-rock with the power of hard rock guitar, strong ballads, and elements of American musical theater.

The band is best known for the hit songs "Lady" (#6, 1975), "Come Sail Away" (#8, 1977), "Babe" (#1, 1979), "The Best of Times" (#3, 1981), "Too Much Time on My Hands" (#9, 1981), and "Mr. Roboto" (#3, 1983). Other hits include "Show Me the Way" (#3, 1990), "Don't Let It End" (#6, 1983), and "Renegade" (#16, 1978). The band has four consecutive albums certified multi-platinum by the RIAA.