On the 1st Floor, Ispahani Centre, Nungambakkam High Road with views facing the road as well as the side by lane, its probably the most vantage, sprawling and leisurely cafe hang out on Nungambakkam High Road.
Its a fairly big place and you can hang out - they don't hurry you or shoo you (even if you are a big gang and have been around more than a while :)
Ambience is good. Service is good - though, when it is full, you gotta push thru a bit to get your service. Their service is quite intelligent - for example, when they saw, once, that my entourage had seniors and we had forgotten (in all the banter the group was engaging in, to tell them sugar preferences) they were thoughtful to come back (after taking the order) and reconfirm how many sugar-free coffees :)
Price is moderate (not expensive). I am not saying value for money because I am not too impressed with their range. I don't get specialty hot chocolate & other discerning stuff. But, yes, very good samosas and cappucino.
A snack+drink outing for two could easily be done within Rs.400/- with oodles of leisurely hang out time with a view of the busy Nungambakkam High Road (that sure is premium :)