I use Redgate SQL compare for this (by comparing to an empty DB), as well as for doing upgrades between all my DB versions (I save a copy of the DB for each released version, and then just do a compare between current and previous to get a change script for that version).
I have found the "Generate Scripts" does a bad job in some cases with dependencies - eg, it will try to create a stored procedure that uses a table before the table is created, causing the script to fail. I'll accept I'm possibly using it wrong, but SQL Compare "just works". The scripts it generates are also enclosed in a transaction -- so if something fails, the whole change is rolled back. You don't end up with a half-populated or half-upgraded database.
Downside is that this is a commercial tool, but IMHO worth the money.