WHETHER GIFT DEED IS REQUIRED TO BE REGISTERED OR NOT

No, There is not any requirement like that.................... 

It is preferable to make a gift deed on a Rs. 100/- stamp paper.

No need for registration.

I don't think any Stamp paper is required (for cheque/ cash gifts). Writing a plain typed note on a paper will generally suffice. Mention the names of persons, their relations and that the gift is being given out of love and affection. Sign the said Gift note and preferably in presence of 2 witness. Registration is also not required, but if the parties desire they can get the same registered the Reg. Fees for the same would be Rs. 100/-. Registration will make the evidence of Gift firm (Only in case that if the person who gifted dies his/ her legal heirs would not dispute and claim the amount back in future)

No. Gist deed is not required to be registered.