I wouldn't say so of the late seventies, but nowadays I'd say that an overlooked/unappreciated guitarist would be good ol' Peter Frampton. He's put out a few albums over the past decade, including 2003's "Now". In fact, he was recently on tour promoting the album but his guitarist/keyboardist died.

R.I.P. Bob Mayo (1951-2004)

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"...Did we do anything after this?"

"I've a feeling we did..."