Imam Al-Suyuti:
“To commemorate the mawlid which is basically gathering people together, reciting parts of the Quran, narrating stories about the Prophet's birth and signs that accompanied it, then serving food and afterwards departing, is one of the good innovations, and the one who practices it gets rewarded, because it involves venerating the status of the Prophet and expressing joy for his honorable birth.” (Alhawi lil-Fatawi)

Imam Shamsu Din bin Nasir Al Dimashqi.
"This Abu Lahab, unbeliever , who has been dispraised, will stay in Hell forever. Yet, every Monday his torment is being reduced because of his joy at the birth of the Prophet." How much mercy can a servant expect who spends all his life joyous about the Prophet and dies believing in the Oneness of Allah? (Mawlid al Sadi fi Mawlid Al Hadi.)

Imam Ibn Al Jawzi
"It is security throughout the year, and glad tidings that all wishes and desires will be fulfilled."

Imam Abu Shama (Imam Nawawi's shaykh)
"One of the best innovations in our time is what is being done every year on the Prophets birthday, such as giving charity, doing good deeds, displaying ornaments, and expressing joy, for that expresses the feelings of love and veneration for him in the hearts of those who are celebrating, and also, shows thankfulness to Allah for His bounty by sending His Messenger, the one who has been sent as a Mercy to the worlds." (Al ba'ith ala Inkar Al bida` wal hawadith, Page-23)

Imam Al Shihab Al Qastalani (Al Bukhari's commentator)
"May Allah have mercy on the one who turns the nights of the month of the Prophets birth into festivities in order to decrease the suffering of those whose hearts are filled with disease and sickness." (Al mawahib Al Ladunniya, 1-148)

Mufti of Mecca Ahmad ibn Zayni Dahlan
"To celebrate the Mawlid and to remember the Prophet is accepted by all the Ulama of the Muslims." Most of the following quotations are taken from that work. (Al-Sira al-nabawiyya wa al-athar al-muhammadiyya, page 51)

Imam Subki
"When we were celebrating the Prophet's birthday , a great uns (familiarity) comes to our heart, and we feel something special."

Hafiz al-Dhahabi:
"He [Muzaffar] loved charity (sadaqa)... and built four hospices for the poor and sick... and one house for women, one for orphans, one for the homeless, and he himself used to visit the sick... ….As for his celebration of the Noble Mawlid al-Nabawi, words are too poor to describe it. The people used to come all the way from Iraq and Algeria to attend it. Two wooden dais would be erected and decorated for him and his wife... the celebration would last several days, and a huge quantity of cows and camels would be brought out to be sacrificed and cooked in different ways... Preachers would roam the field exhorting the people. Great sums were spent -as charity( Siyar a`lam al-nubala')

Imam Shawkani
"It is permissible to celebrate the Prophet's birthday." (Al-Badr At-tali)

Hafiz Ibn Hajar al-Haytami
"….Ibn Hajar continues, “One gives thanks to Allah for the favor that He gave on a particular day either through a great good, or through the averting of a disaster. That day is celebrated every year thereafter. Thanksgiving entails various forms of worship like prostration, fast, charity, and recitation of Qur'an, and what greater good is there than the advent of that Prophet, the Prophet of Mercy, on the day of Mawlid?"

Imam Ibn Kathir:
“The Night of the Prophet's birth May Allah bless him and grant him peace, is a magnificent, noble, blessed and holy night, a night of for the Believers, pure, radiant with lights and of immeasureable price” (Dhikr Mawlid rasulullah wa Rida' atihi)

Dr. `Isa al-Mani` al-Humayri, Department of Awqaaf, Dubai
Yes we should celebrate it every year.
And every month and every week.
And every hour and every moment.

There are others who wrote and spoke about Mawlid, such as Imam Al Sakhawi, Imam Wajihu Din bin Ali bin al Dayba' al Shaybani al Zubaidi, and many more , which we will not mention due to the limited space available. Among those scholars is the Maliki jurist Taaj Ad-Deen Umar Ibn Al-Lakhmi Al-Sakandari known as Al-Fakahaani(Al-Mawrid fil Kalaam Ala-Mawlid), As-Syooti(Husn Al-Maqsid fi a’mal al-mawlid. Page-251-262).

Many books were written on the Prophet's birthday such as the stories of Ibn Dahya, Muhy Ed-Deen Ibn Al-`Arabi, Ibn Taghrabik, and Ahmad Al-`Azli and his son Muhammad, Imam Mohammed bin Abu Bakr Abdullah Al Qaisi Al Dimashqi(Jami' Al Athar fi Mawlid, Al Nabiy Al Mukhtar), Imam Al `Iraqi(Al Mawlid al heni fi al Mawlid al sani), Mulla `Ali Al Qari(Al Mawlid Al rawi fil Mawlid al Nabawi), Imam Ibn Dahiya(Al Tanweer fi Mawlid Al basheer Al Nadheer), Imam Shamsu Din Ibn Al Jazri(Urf Al Ta'reef bil Mawlid al shareef), Ibn al-Jawzi((booklet of poems and Sira entitled Mawlid al-arus)

Even the Salafi Sheikhs permitted to celebrate the Milad Sherif. See the front page what Ibn-Taimiyah and Ibn Abdiwahab said about Milad.

Ibn Qayyim al Jawziyyah (Student of Ibn Taimiyah):
"Listening to a good voice celebrating the birthday of the Prophet (s) or celebrating any of the holy days in our history gives peace to the heart, and gives the listener light from the Prophet (s) to his heart, and he will drink more from the Muhammadan spring -a’yn al-Muhammadiyya"(Madarij as-Salikin, Page 498)

Sheikh Yusuf Al-Qaradawi said:
Sa’d Ibn Abi Waqqaas said that they were keen on telling their children the stories of the Prophet's battles just as they were keen on teaching them the Qur'an. Therefore, they used to remind their children of what happened during the Prophet's lifetime so they did not need to hold such celebrations. However, the following generations began to forget such a glorious history and its significance. So such celebrations were held as a means of reviving great events and the values that we can learn from them(Fatawa date April 19 2001).

http://www.livingislam.org/n/mwld_e.html