Hi
Nirenj: Saw you inquiring after various lenses.
Perhaps the easiest way to know what you really want/need is by listing your preferences in shooting. This is very personal and no one else can do this for you. Here's an example of a list (#1 being your most fav topic. Please note that this list is just an example and by all means not exhaustive at all):
1. Portrait
2. Macro
3. Sports/Action
4. Landscape/Scenery
5. Street photography
You will save yourself a lot of guess work when you know which topics interest you most, which give you the best 'feel good' feeling, which generate the most enthusiasm when you shoot. Don't think of 999mm or 9mm first. Otherwise, you'd be buying a lens and then have to shoot to suit the lens instead of developing your areas of interests ...
My next advice, once you have a list in hand, is to research various magazines and forums such as
www.dpreview.com or
http://lens-reviews.com/ (this one some times isn't up to date) for your #1 topic .. then you cross reference with a local content at CS (we have a thread on lenses, i think). For magazines, you can visit a bookstore and easily browse: Practical Photography, DSLR User Magazine, etc. They have the latest lens reviews.
Then, when you've found your second lens (and have lotsa fun with it), you'll find that your initial list may change after lots and lots of shooting.
So, the process above? Rinse and repeat :bsmilie:
Hope this helped.