Etymology of the Word “God”
(Anglo-Saxon God; German Gott; akin to Persian khoda; Hindu khooda).
The root-meaning of the name (from Gothic root gheu; Sanskrit hub or emu, “to invoke or to sacrifice to”) is either “the one invoked” or “the one sacrificed to.” From different Indo-Germanic roots (div, “to shine” or “give light”; thes in thessasthai “to implore”) come the Indo-Iranian deva, Sanskrit dyaus (gen. divas), Latin deus, Greek theos, Irish and Gaelic dia, all of which are generic names; also Greek Zeus (gen. Dios, Latin Jupiter (jovpater), Old Teutonic Tiu or Tiw (surviving in Tuesday), Latin Janus, Diana, and other proper names of pagan deities. The common name most widely used in Semitic occurs as 'el in Hebrew, 'ilu in Babylonian, 'ilah in Arabic, etc.; and though scholars are not agreed on the point, the root-meaning most probably is "the strong or mighty one
when did Ibn e Batuta or his narration of his travels and his findings on the state of Islamic empire at that time become any authority or ideal of Islam?
The best is to say Allah, as this is the word repeated in Quran and all those 99 names are attributed to it. Read surah Ikhlas and it will clear the concept.
It really doesnt matter whether one says Allah or Khuda hafiz.
I prefer to use the word Allah because the word Allah reminds me that Mohammad was speaking about a God that was worshipped by the Arab Jews and Christians too, before Mohammad came on the scene. This demonstrates a sense of continuity that is important to me. It reminds me that Allah is the God of the Torah, Injeel as well as the Quran. For example, Arab history records that there was a Jewish rabbi named Abd'Allah who accepted Islam. The way I see it, a Jew wouldnt be named worshipper of Allah (Abd'Allah) if Jews didnt believe Allah was their God in those days. Similarly, archaeologist have discovered an ancient 6th c. Christian inscription, that predates Islam, with the word Allah for God in a church. The same word Allah is also the word used for God in the Christian Bible. These examples demonstrate the continuity of God's message from prophets, Moses, Jesus and then Mohammad p.
As far as the suggestion that khuda was used for idols or fire by the Persians, so it shouldnt be used. That is silly, in my opinion. As far as I recall, pagan Arabs were known to worship Allah as the father of ALat Uzza and Manat. They wanted Mohammad to concede to this arrangement, which he refused. The 360 idols were kept in the house of Allah by these pagans. So, the name Allah too had been defiled by the pagan Arabs, before Mohammad washed it clean of their idolatry. Therefore, in my opinion, it cannot be argued that the word khuda or any other cannot be cleansed of idolatry, as long as it is a good word.
I think its best to call Allah (swt) with the names that he himself has called Himself with. Avoid the debate... do what is best, and "suspicion-free"...
Like the difference amongst god and God in English language, there is some difference between khuda and Allah. Khuda is used for a lot of purpose, Hindus may use it for their gods as well. When some one says Allah, he is definitely trying to say just THE ONE. Secondly it is the name Allah has used for him in Holy Quran. So it is always good to say, Allah-Hafiz.
Like the most famous quote by the prophet, that all deeds depends upon niyyat, so if you say Khuda-Hafiz while you mean Allah when you say Khuda, then both words have the same meanings, at least according to the user. But the listners may take it otherwise. For example Hindus and Sikhs, who are used in living amongst the Muslims, use these words too, even when they are in their own relegious communities. They mean the god they believe in, when they say this.
Just to end, whether you use Allah-Hafiz or Khuda-Hafiz, it depends what you are trying to mean with your heart, so only the user or Allah knows this and only Allah will pay you back for your deeds.