Ḥabīb ‘Alī is from the renowned ulama of Yemen, from the Ḥabā`ib family, which has produced great Muslim Scholars for centuries. The Durūs wa Khuṭab section of his website has hundreds of hours of Arabic audio lectures. His website can also be viewed in English, and access lectures with parallel English translations.
The recording quality of some of the lectures is unfortunately quite poor, but the general level is okay. Just play around until you find one that’s easy to listen to. Also, you will have to get used to the Yemeni pronunciation of the letter qāf, which is pronounced like the Persian gāf.
Shaykh Bin Bayyah is a Mauritanian scholar, respected throughout the Muslim world for his erudition and piety. Of late, he has been involved in a number of both academic and community-building projects with prominent Muslim scholars in the West.
Although the audio (ma’riḍ al-ṣawtiyyāt) and video (ma’riḍ al-mar`iyyāt) sections are unfortunately relatively limited, the website does have a lot of reading material, including downloadable books and research papers, and even a little poetry.
Shaykh al-Dedew is also a Mauritanian scholar, and ranks amongst the most impressive ulama of this age. He comes from an educational tradition in which great emphasis is placed on memorization, which is clear from his lectures. Shaykh al-Dedew himself has memorized the six well known collections of aḥādīth. The Masmū’ section of his website has hundreds of hours of muḥāḍarāt (speeches), dawrāt ‘ilmiyyah (academic lectures) and khuṭab jumu’ah (Friday sermons).
Shaykh Mūsā is a Saudi scholar (who, interestingly enough, also works as a pilot!). He has a particular interest in Muslim history, which is what his website is dedicated to.