There is no single answer to your question. It depends on the circuit goals. For example, if you design current mirrors, or design for high frequency or good THD, then you want bigger Vdsat, like 200mv, 300mv (if you can afford). If you need diff pair, or low power circuits, transistors with better current efficiency, then you design with small Vdsat - in the order of 100mV, 150mV. If you need higher output swing you also will need small Vdsat. If you design for low voltage, Vdd=1v to 2v then you will not be able to use more than 150mV perhaps.
If you don't care about all these things you can find a sweet spot where you get both good frequency response and good current efficiency. And BTW, with modern nm technologies, Vdsat as a design parameter looses sense. For example in 65nm and 45nm when the simulator shows Vdsat=Vgs-Vth=0 you are nowhere close to subthreshold, but rather in moderate inversion. Vdsat of about -100mV is better indication of weak inversion - of course if we believe the models.