[DriverR]

My two cents.....
I would go for the Esteem. Why? MUL service, fantastic engine (old but gold), tough (parents drove their esteem all over the North East, all seven states + West Bengal), reliable (never broke down durin a trip), looks (Ya, call me mad, but I like the VXi looks)
Drawbacks include lousy quality of power windows, esp the front passenger side (once failed in the down/open state just before a planned trip. Had to take an alternative vehicle instead) , you may feel intimidated sitting relatively lower than other cars.
I may not go for the petrol Indigo. Tata has never been strong on petrol engines, leading to high maintenence cost. The intial petrol Indicas and Indigos had their share of problems. While the petrol Indica engine seems to have been sorted out, no one (including Tatas) has said much on the petrol Indigo. (Are both cars sharing the same engine??? If so then, possibly the petrol Indigo engine should be fine)
Second option would be Ikon.
Accent is actually a decent car and would have been my next choice, but as you mentioned, it's future is uncertain.
Logan...... man, I would not buy it. Call it a negative mind-set but I do not think the 1.4 petrol is worth paying for. For the same money you can get a much better featured midsizer.

You may want to consider resale value after 5 years. If we were to assume that Esteem, Ikon and Accent gets discontinued in two years time, then which one will have the best resale value, I really cannot tell. It is too early to even guess Logan's resale value, as it all depends on how well it sells in the coming months.