Sure, I'm using photoshop + illustrator at the same time, using large files. Outlook, Mail, chrome, iTunes, and firefox are all open as well. On my Mac Mini I use a 25" screen and a 19" screen (this is a MBPr limitation without connecting it to the screens, I know).
The speed of the MBPr running graphics-intensive software / virtualization is incomparable.
I also use Parallels and run autocad in windows.
Thank you!