Slipstreaming is surely very popular as it helps you save time for new installs and more importantly to avoid the known issues (too many to be listed here) which can cause failures in setup. I felt that the the steps to create the merged media were confusing for the first timers. I also saw few folks on the blogs wondering if there is a tool to automate the slipstreaming.
Here is a tool which should assist you in creating the Merged slipstream media for SQL 2008.
Any feedback? Put it on the Codeplex discussion