Zoli Band
This was a pop project by members and roadies of hardcore punk band Ignite. Their early stuff was mostly acoustic and folky, their later stuff was more melodic rock like the Foo Fighters. Their only studio album (they also have a live LP) is excellent, certainly in my album top 20, and their song "Painful" is one of my all-time favorite songs. Unfortionately, their records never really reached anyone else than probably a few hundred of the more open minded Ignite fans.

Post-Pet Sounds Beach Boys
Many people think that the Beach Boys didn't do much between "Good Vibrations" and "Kokomo". But they actually made their best albums after the big public stopped caring. Albums like "Wild Honey", "Friends", "20/20" and "Sunflower" are all masterpieces. They were total flops, but I've never read a single negative review of any of them.

Sagittarius
A studio project by producer Gary Usher and singer Curt Boeccher, who were both highly respected in the LA music scene in the 60s, but mostly unknown to the big public. Their album "Present Tense" isn't all that great, but its two singles, "My World Fell Down" and "Another Time", are two of the greatest and most underrated songs from the 60s.

squeeze

orange juice

Prefab Sprout
Creedence Clearwater Revival
Isley Brothers
Tom Tom Club

i agree with what Joost said about the Beach Boys later albums, they are some of the
best BB records! their Sunflower album is a materpice in my opinion! & it's very underated.

I'm not sure who's most underrated, but after listening to a Mary Wells collection the other day at a friend's place, I'll certainly jump up and throw in a plug for the lady, despite the fact that she's not a band and therefore maybe not quite within the bounds of your question.

SLOAN.. nuff said they are amazing and straddle a weird line between indie and major label success here in Canada. they formed in 91 and were always on the cusp of major label exposure till Geffen decided they weren't marketable enough PLEASE check these guys out..


The Other Man...


The Rest of My Life

The GTO's
The Groupies
Fanny

World Party Give It All Away. The bass player is David Catlin-Birch most recently of The Bootleg Beatles.


XTC Dear God

The Spiders From Mars (This great band were overshadowed by Ziggy which is a pitty)

T. rex ( A criminally forgotten band, Bill Legend (Drums ) Steve Currie (Bass ) two of the best musician's of the 70's , check out Ringo's Born To Boogie Film , if proof be needed and Bolan could play some mean guitar ?

Sagittarius - My World Fell Down:

Quoted from BlueMeanie

World Party Give It All Away. The bass player is David Catlin-Birch most recently of The Bootleg Beatles.

I think Chris Whitten is playing drums with them again. I'll ask him over at the drum forum, but i'm pretty sure he said he was.

I've never listened to them, but have heard good things about them.

Quoted from tkitna

I think Chris Whitten is playing drums with them again. I'll ask him over at the drum forum, but i'm pretty sure he said he was.

I've never listened to them, but have heard good things about them.

Chris played with them on their comeback tour in the States last year, and I think when they supported Steely Dan in Oz. he's occasionally to be found on the World Party Forum. It would be nice to know if the new album is coming out this year.

World Party...Also had Guy Chambers in who wote most of Robbie Williams solo stuff. Biggest hit in the UK...Almost one hit wonder really... 'Is it Like today'. I have the album on cassettes somewhere. Are they still playing then?

Quoted from An Apple Beatle

World Party...Also had Guy Chambers in who wote most of Robbie Williams solo stuff. Biggest hit in the UK...Almost one hit wonder really... 'Is it Like today'. I have the album on cassettes somewhere. Are they still playing then?

They started up again in 2006. Well, World Party is basically Karl Wallinger and whoever else is around at the time. Karl suffered a brain aneurysm in the beginning of 2001 and spent the next 5 years recovering.

He and Guy Chambers fell out a long time ago after Chambers hijacked his band and re-recorded 'She's The One' with Robbie Williams. Mind you, the money he made for it kept him going while he was ill.

Jethro Tull are a underrated band as are ELO .

Quoted from DaveRam

Jethro Tull are a underrated band as are ELO .

ELO were huge, how does that make them underrated? Jethro were quite big as well.

I always liked ELO BlueMeanie and yes they were a very big band , but i remember at the time a lot of people turned there nose up if you said you were a fan , poor man's Beatles thats what one of my friends used to call them.
And although i think they are getting some respect now , there still not spoken of in the same breath as Pink Floyd ,Led Zeppelin who i think they are as good as,  popular yes but they don't sit at the top table , were they should be in my opinion .