According to my Dell rep:
"Adobe announced the release of the Creative Suite 5.5 products on April, 11th. As a result of the new release, pricing for these products is increasing anywhere from 6% - 19%. Now is a great opportunity to take advantage of the current CS 5.0 pricing and receive a free upgrade* to CS5.5 once it starts shipping in early May. The last day to place a CS5.0 order is April 27th so don’t wait!"
*Note: I have not found confirmation regarding the free upgrade.
Update From Bob at Digital Illusion, Inc.:
"The cutoff date for the free upgrade from CS5 to CS5.5 is March 10, 2011.
If CS5 or an upgrade to CS5 is purchased on or after March 10, 2011, you can request the free upgrade to CS5.5 from Adobe.
I talked to Adobe customer service and was given this date. However if you have been an Adobe software user for years and missed the cutoff by a few days, like I did, they may grant you an exception and give you the free upgrade. I purchased my upgrade to CS5 on April 28 but was granted a free upgrade to CS5.5 after talking to Adobe customer service."