Yesterday I've had the following open:
Notepad++ (with 6+ open tabs), Notepad, Trillian, Opera (with 7+ open tabs), Adobe Flash Builder 4, Adobe Photoshop 7 (with 6+ open files), Windows Explorer (4-5 instances), File Zilla. I think there were 2 or 3 more. Opera died on me since I was recompiling the flash site many times so Opera went over 700 MB. xD