Software Virtualization Solution 2.0, announced this month, is under great attention for the free personal edition released by Altiris.
Quoting from PC Magazine review:
Anybody can use Altiris Software Virtualization Solution 2.0 to put a safety wrapper around software installations and to package installations for import on other computers. Power users can do quite a bit more by manipulating advanced properties and using the commandline interface. Give SVS a try! Just remember that if you later uninstall it, you’ll have to reinstall any virtualized applications — at present there’s no way to merge them into the underlying base system.