I am a very heavy user of OmniFocus. It has many ways to enter information. For example, you can use the "Quick Entry Window", which is great for creating an item with a project, context, and optional description.
But sometimes I am not in OmniFocus and don't have any text selected. This means there is nothing for OmniFocus to treat as a clipping. As a result it won't bring up the quick entry window.
So, I wrote my first Dashboard widget. It has a text area where you type the text for your item and a "Send It" button. When you click the button or hit enter in the text area, a new item is sent to your inbox.
I submittted it to Apple for inclusion in their download area for dashboard widgets download site. Until it shows up there, you can get it directly from here.
[Updated 2008-07-17 21:05]
Someone pointed out that I had forgotten that there is a separate keystroke to bring up the quick entry window without having any text selected. This eliminates much of the purpose of this widget unfortunately, unless you spend a lot of time in the dashboard anyway. At least it was a good learning exercise... :-)