Avinash,
No demands from just some suggestions.It's that most are asking for security,AVira premium is definitely good choice.But security addons like Hitman Pro 3.5,USB disk security/navieus usb antivirus,Sandboxie,Returnil,WinHex,etc.
Others type of S\W's can be encryption for hard-drive and pen-drives[will let you know later]
Finally,Backup S\w's like HandyBackup,Marcerium,Acronis,Mozy,etc.
Like I said b4 these are only suggestions Avinash,so problems,if you want find anything interesting I will point out their e-mail support which are quite easy to find.