In addition to the persons mentioned, some other gedolim who attended university:
Rambam
Sforno
Rav Hildesheimer
Rav Hirsch
Rav Herzog (PhD in Chemistry — in his dissertation research he found the source for techelit)
Rav Soloveitchik (also his wife, both brothers, son, both daughters, and both sons-in-law, all of whom earned doctorates except for his brother who was a lawyer as well as a rosh yeshiva)
I could go on and on but it is late.