Excellent Idea for a thread. One of the most under-rated century is Dilip Sardesai's 212 in the first test against WI in 1971.
1st Test: West Indies v India at Kingston, Feb 18-23, 1971 | Cricket Scorecard | Cricinfo.com
Much has been made of Sunny Gavaskar's performance in that series and deservedly so, but IMO it was Sardesai who set the tone by scoring a double tone in the first test of the series. Highly underrated Indian cricketer and the most underrated innings by an Indian batsman IMO.