Tov Are Jacobsen

Dell seems to have the greatest discounts at the end of a quarter.

Dell's fiscal year ends on the Friday nearest to January 31st.

Assuming Dell has met it's margin requirements, end of quarter is a good time for them to boost revenue.

So for purchasing in the first quarter you might for instance try:

April 30.
July 31. 2008
October 31. 2008
January 30. 2009 (Friday).

Remember

In addition, you are likely to find additional  additional discount on the web as a coupon, try asking in dell discussion forums around the web a few days prior to purchase.

In addition....

Self service on the web as a regular consumer will usually give you a better deal than calling sales or buying through a small company.