So this thread is about which bands did you discover that you had never heard of previously, that you saw as a support act at a gig you attended and went on to love.
For me these four.....
James (supported The Smiths at Palace Theatre, Manchester 1985)
Inspiral Carpets (supported The Wedding Present at The Ritz, Manchester 1988)
The Thrills (supported Morrissey at Royal Albert Hall, London, 2002)
Girl In A Coma (supported Morrissey in New York / Boston 2007)
Honourable mentions to
The Comsat Angels (support to U2 at Warwick Uni 1981)
The Red Guitars (support to The Smiths at Lanchester Poly, 1984)