For the Excelsior-Class, in the DS9 tech manual, it says that they have a crew complement of 750--exactly the same as a Nebula-Class.
I find that hard to believe. The Nebula has a far greater internal volume than the Excelsior, how the two ships could share the same number of crew baffles me. In my head the crew on the Excelsior-Class is around the 550 mark.
Commander Austin Harris, First Officer, Deep Space Nine (by FltCpt. Bossco)
8.01 - Darkest Before Dawn
(Chapter 8 added, 12/09/2015)