VB won't run on my Linux machines at all, and I have serious misgivings about Mono being able to run GUI apps reliably - I haven't yet seen any C# Linux apps.
On the other hand, I use the LBE LDAP Browser/Editor often under both Windows and Linux - it's a Swing app. So is my EJBWizard (http://www.mousetech.com/EJBWizard.html). Or, if you prefer something major, there's apps such as ArgoUML (http://www.tigris.org) which not only is a Swing app, but thanks to Java WebStart can keep itself updated automatically - unlike traditional Windows apps.
Customer surveys are for companies who didn't pay proper attention to begin with.