All my web design is now done on the iPad. I use HTML Egg Pro - a powerful template-based site builder.
Sound editing is a breeze with Twisted Wave. I used it to edit many of the audio clips on this site.
Cute CUT Pro is my video editor of choice. It can do amazing transitions, effects and overlays.
Image editing is a breeze with ArtStudio for iPad. It can do most of the things Photoshop can do.
For more elaborate sound design, Music Studio can handle many tracks, as in this orchestral arrangement.
Clipish Pro can find almost anything I need in the way of photos or clip art. Most is free for personal use.
App Store apps
for web design

Click on an image for a larger view. Click on the text to see the app on the App Store