There is a third recovery mode not mentioned above. The recovery mode ultimately determines how large the LDF files become and how ofter they are written to. In cases where you are going to be doing any type of bulk inserts, you should set the DB to be in "BULK/LOGGED". This makes bulk inserts move speedily along and can be changed on the fly.
To do so,
USE master ;
ALTER DATABASE model SET RECOVERY BULK_LOGGED ;
To change it back:
USE master ;
ALTER DATABASE model SET RECOVERY FULL ;
In the spirit of adding to the conversation about why someone would not want an LDF, I add this: We do multi-dimensional modelling. Essentially we use the DB as a large store of variables that are processed in bulk using external programs. We do not EVER require rollbacks. If we could get a performance boost by turning of ALL logging, we'd take it in a heart beat.