THE question was floated around the office recently as to what is the longest continually running band in the world.It's a tough one. Vocal group The Drifters began in 1953 but now there are about four or five different Drifters touring at any time, depending on court cases. Then there are groups like folk act The Brothers Four (formed in 1957) and Aussie doo-wop band The Delltones (formed in '58), both of which have only one founding member left.But what's even harder is finding a band that still has all its original members or even a line-up that's been unchanged for a long period. We decided to take the harder route and find five long-running line-ups.ZZ Top - unchanged since '69TEXAN good ol' boys ZZ Top truly are the elder statesmen of rock. The band formed in 1969, played their first gig the following year and haven't changed a whisker since. The band's glory days are behind them - their biggest hits came out in the '80s and they haven't had a top 10 album since 1990 - but ZZ Top continue to tour and record, with original line-up Billy Gibbons, Dusty Hill and Frank Beard still going strong. Incidentally, Beard is the one without the beard.Golden Earring - unchanged since '70DUTCH rock band Golden Earring have evolved markedly since they formed in 1961 as a bunch of teenagers. When they released their first album in 1965, they idolised The Kinks and The Beatles, but eventually became a psychedelic act before finally settling on a hard rock sound. Only two founding members remain (vocalist/guitarist George Kooymans and bassist/keyboardist Rinus Gerritsen) but their line-up hasn't changed since 1970. They've released 24 studio albums but their biggest international hit remains the 1973 driving classic Radar Love.Rush - unchanged since '74LOVE 'em or hate 'em, Canadian prog rockers Rush are veterans. Formed in 1968, the band settled on its current line-up in 1974 with the joining of drum legend Neil Peart. Their self-titled debut came out the same year, thus beginning a lengthy and influential career (Metallica and The Smashing Pumpkins list them as influences) that has incorporated prog, synth-rock, hard-rock and classical music. Rolling Stone magazine once called them the "Trekkies of Rock" and they remain ignored by the Rock And Roll Hall Of Fame, but they have a cult following like no other.U2 - unchanged since '78ON a September day in Dublin in 1976, a bunch of seven lads got together and jammed, calling themselves Feedback. Paring back to a five-piece and changing their name to The Hype over the following year, the band eventually became the mega-selling quartet known as U2 in 1978 when they finally kicked The Edge's brother out of the band. The line-up hasn't changed since, with Bono, The Edge, Larry Mullen and Adam Clayton slowly taking over the world from then on.Aerosmith - unchanged since '84THE Rolling Stones have been around longer (they formed in 1962), but their line-up has only been unchanged since 1994. So Aerosmith take fifth spot on this list with a stable line-up since 1984. The bad boys of Boston formed in 1970 and by 1971 hit upon their current line-up, but in 1979 guitarist Joe Perry left, followed soon after by guitarist Brad Whitford. Both attended an Aerosmith show in 1984, decided they wanted back in and the band hasn't looked back since. Did we miss any? Let us know.