Hi Siddharth,
I suppose the answer to your questiond depends on what you want to achieve,
but as a genertal rule of thumb, I'd say group policy is very important and
can save administrators a lot of time.
Basically, you can use group policy to definite settings across your
network, whether it be to certain users, groups, sites, OU's or domain.
You can also use it to roll out software.
It all depends how big your network is, whether you use a domain or not, and
what you're trying to achieve
Paul