I must admit (somewhat shame-facedly) that I never watched too many Hindi movies when I was a kid. So the only Rajesh Khanna movie I recall watching was Haathi Mere Saathi (probably the first Hindi movie I saw, although not in its entirety). I only discovered Hindi movies properly when I was in the US in the late-1980s ironically.
Although I missed all the great Rajesh Khanna movies (only seeing parts of Aradhana quite recently, that too dubbed in Bengali..!!), I was intrigued to discover through his obituaries that he was engaged to Anju Mahendru for 8 years. I had actually only heard of Anju Mahendru as the (failed or largely unsuccessful) actress who had been engaged to Garry Sobers, having read about this in Conrad Hunte's terrific autobiography -- and later in Sobers' own (rather poorly written) one.
It was quite astonishing to discover that this unfortunate lady had been ditched TWICE in life by two of the leading icons of her time, one in cinema, the other in sport. (Actually the Sobers liaison didn't work because her parents/family didn't allow it, as far as I recall...Rajesh Khanna seemed to have decided to go with Dimple almost at the last minute -- leaving the house he shared with Anju Mahendru for her to live in, and going off to instead marry the latest young star!).
This, by the way, is Anju Mahendru:
http://www.rediff.com/movies/slide-show ... 120722.htm