The best option is to ask people who live nearby as in my experience internet provider's services and speed changes with area to area some times; just ask neighbours their experience about BSNL as it has been seen that many times the service is degraded in proportion to the distance from the exchange
And about the fastest i do not know but check the websites of Airtel and Reliance : Wimax and Tata Indicom too. . . .alternatively if there is a Optical Fibre Broadband ISP near your area then go for it if you need the cheapest rates
Most of Unlimited packages come with relatively lower speed than limited one.
Think twice before compromising download limit or Speed.... Choose best plan
Speed of the ISP depends on the area one lives in, i totally agree with John,
I hv an MTNL Triband Connection, it works really gr8 at my home coz reason: Im closer to the MTNL Telephone exchange, where as Airtel Sucks in my area..but in sum other areas, this will be the other way round./.
So, (TO the Original Poster): Enquire abt the performance of the ISP in the area u live in and u will be in a best of positions to make a decision..
--------------