The splash screen is the first thing that users see when they enter your application. You should think of it as the cover of a book — a good first impression says a lot. Decide on your deployment platform and stick to the color palette specific to that platform. Windows 3.1 VGA uses a 16-color palette and Windows 95 uses a 256-color palette. If you create a custom palette and load it with your application, you run a significant risk of having the user experience color shifts when switching between applications, especially in Windows 3.1.
Many corporate GUIs require a login window for security. Why not incorporate the splash screen with the login window to add visual aesthetics to the entry point of your application? This can also be a means of branding or identifying the application.
Overall, make the splash screen a visual metaphor that clearly and accurately articulates the process performed by the application.