It has been a while since I have been in charge of Full Model implemetation but DBArtisan of Embarcadero, ERWin of Computer Associates and Sybase Power Designer are the most Famous ones (that I know of ). I have heard that MS Visio is getting better and that can do the Reverse engineer too but honestly I haven't used it for DB Modeling.
If you perform a search on the site I am pretty sure there are threads talking about just that