which data card connection to go for

Hello ,

I have bought a laptop. For the internet connection I want to use the wireless connection so that I can be online whenever I want to. The problem is that there are so many data card connection in the market – reliance, airtel, tata indicom, I don’t know which one to buy. Which one of these is the fastest and which one would be a perfect buy.
Please if any one of you has any info abt this do lemme know and also how much will it cost.

Mousumi