A W4 calculates how much federal tax is withheld from your paycheck each pay 
period.  There are two basic drivers:  number of dependents and filing 
status.  The higher the number of dependents, the less is withheld.  Married 
and jointly will also have less withheld than married and seperately.  There 
is really no right or wrong answer, only opinion.  If you want more withheld 
each pay period so that there is less of a chance of actually owing $ on 
April 15th, then claim fewer dependents and married and seperately.  If you 
don't want the government to get your $ interest free, but are aware that you 
may owe $ later on (April 15th), then claim a higher number of dependents and 
married and jointly.  I hope that made sense.

DG