Are Arabs are better than non-Arabs? This is what I have heard and I wanted to just to be sure. I have heard it from Shaykh Abu Usamah at-Thahabi.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

We have previously issued Fatwas 81937 and 84769 that preference and superiority in the sight of Allaah is in piety and righteous deeds, as Allaah Says (what means): {Indeed, the most noble of you in the sight of Allaah is the most righteous of you.} [Quran 49: 13] The Prophet , said: "O, people, indeed your Lord is One and your father is one. Know that there is no superiority of an Arab over a non-Arab, or a non-Arab over an Arab, or a red person over a black person, or a black person over a red person - except by piety." [Ahmad] However, this does not mean that it is not possible to find in a given people a characteristic that are not paralleled by others, as the Prophet said: "The descent of people is different…" [Al-Bukhari]

Imaam An-Nawawi said, "If the origins of a person are honourable then the branches would be likewise in most cases, but the excellence and preference in Islam is by piety. However, if piety is coupled with the excellence of family lineage, then that is even more excellent." In addition to this, the Prophet said: "Verily Allaah has chosen Kinaanah from amongst the descendants of Ismaa'eel and He has chosen Quraysh amongst Kinaanah, and He has chosen Quraysh amongst Banu Haashim and He has chosen me from the tribe of Banu Haashim." [Muslim] In another narration, the Prophet said: "I am the best amongst you in relation to family lineage and I am the most pious of you." [At-Tirmithi and Ahmad] Therefore, this is evidence that Kinaanah, Quraysh, and Banu Haashim are of excellence in comparison to other races and tribes.

Sheikh Al-Islam Ibn Taymiyyah said, "The Arabs deserve love and loyalty more than the other races from the children of Aadam, and  this is, of course, the opinion of the majority of the scholars who consider that the Arabs are of excellence over other races and that the Quraysh are of excellence over other Arabs. This is indeed the view of Imaam Ahmad and the texts prove this.… However, the people of theological rhetoric are of the view that there is no excellence or preference of one race over another, and this is the view of Abu Bakr Ibn Al-Tayyib and others. This is also the doctrine of 'Ash-Shu'ubiyah' (a group who hate and oppose the Arabs) but this is a weak view, and it is a view of the innovators."

To conclude, people are of different descent, there are those who are good and those who are bad, however, the Arabs are of excellence and preference that is not paralleled by others. 

Allaah Knows best.