LANDesk sells install shield. It is a very nice packaging solution. If your looking into virtualizing your apps you may want to look into LANDesk Application Virtualization. Talk to your sales person about both.
So this depends on a lot of factors - budget, resources, in house expertise, number of packages, etc... Snapshots should be a last resort in any packaging process. It is just too risky and there are most always other ways to package. The exception would be Ty's recommendation of LANDesk App Virt/Thinstall. If money is not an object go with Installshield. Professional 2009 is about 4 digits, however, you may get away with the Express Version. I have also used the freeware version of Advanced Installer and the product looks stable, and very affordable. In contrast their big boy Enterprise package is $499.00.
There are numerous freeware alternatives - Appdeploy has a small free repackager, and others, but these items have a very short life with mixed support.
Again you can have the best tools, but if you snapshot everything you will have a mess on your hands.