Well, I've been listening to classical music since I was 15. So you're not the only geek Shubho
But, I must admit, I don't know much, as I can never remember the names of pieces I like.
Like most plebians, one of my favourite is of course Beethoven, I really like his dramatic, loud and emotive style.
Mozart I find too pompous for my liking. Although I do acknowledge he is an amazing genius. I can't stand either of the Bachs (too righteous for me). But then again, I don't really like Baroque all that much.
I like Tchaicovsky whose music I find quite melancholy. In fact, Russian composers in general I like..
I'm not really into Operas (yet), so haven't really checked out Wagner, but I know I should because apparently he is the best composer ever :P
And last but not least, I am a great fan of Chopin. I like most of his piano concertos.
Out of contemporary composers, I really like Philip Glass and Michael Nyman's work.
(Nyman wrote the score for movie 'The Piano)