W. O. SMITH, 74, a retired jazz musician who played with such giants of jazz as Bessie Smith, Fats Waller and Dizzy Gillespie, died Thursday in Nashville, Tenn., of cancer. Mr. Smith was a retired music professor at Tennessee State University where he taught for more than 25 years. He had been adjunct professor at the Blair School of Music at Vanderbilt University since 1987. SIR ANGUS WILSON, 77, whose observations of the English middle class made him one of Britain's most distinguished writers, died Friday. He died after a stroke at the nursing home where he had spent his last years, in Bury St. Edmunds, southeast England, fellow author Malcolm Bradbury said. Mr. Wilson wrote some 50 books, among them novels Hemlock and After, No Laughing Matter, The Naughty Nineties and As If by Magic.