For PC use or Home theater use? Are you only looking for a subwoofer or a complete surround sound system?
I only have experience with PC speaker systems. I've used Creative Inspire, and Logitech 2.1 and 5.1 systems. They are pretty reasonable for the price. Altec Lansing is another good brand. I'm not sure about current SL prices, but I think a Creative Inspire 5.1 system is around Rs 8000. BTW if you are interested in Creative, then go for the Inspire series , their cheaper SBS series is not that good.