Logesh,
I remember reading a post on this forum (...somewhere) that there is a version of Knoppix called Gnoppix that has Gnome instead of KDE. My own personal preference is in fact Gnome but I also like KDE. IMHO I would encourage you to switch over. I don't see why a person can't download and install Gnome after if they've done a HDD install of Knoppix (maybe someone can help me out here if it can be done).