I guess I'm not the right person to talk about 'thambikku endha Uru.' (I'm still a young, you see.) I don't recall seeing it in one piece at all, and at any rate, it never made so much of an impression during my growing-up years. On the other hand, 'guru sishyan' is a personal favourite (and certainly Rajini's best comic turn) and I remember enjoying 'rAjAdhi rAja' a lot too.