Lots of people would love to have a tab that just opens directly to a view of their choice. Unfortunately, standard object tabs can only open the relevant standard overview page, which shows a list of recently viewed cases -- that page can't be preset to open a certain view as soon as you hit the tab. However, you can create a custom tab which will instantly redirect itself to the view you'd like. Here's how.
The most common request I get is to create a tab for views on Case, so that's the example I'll give here. Of course, this technique can be used to create a tab for any kind of view for any object.
First, navigate to the view you'd like to tab-ify by going to the overview page and selecting that view. In my case, I'll go to the Cases tab and click on the Open Cases view, which is a view I created that shows all the open cases in my org.
Save the URL of this view; you'll need it later. It will look something like
Now go to Setup->Customize->Create->Tabs. Click the New button under Web Tabs. Set it to Full Page Width. Set the Tab Type to URL, and give it a label that makes sense (I called mine "Open Cases" but you can call yours "Cases" if you intend to hide the normal case tab -- just make sure you don't end up with 2 tabs labelled "Cases"). Pick any Tab Style -- it's going to redirect to the Case tab anyway so this doesn't matter.
On the next page of the wizard, enter the following in the Button or Link URL:
Don't forget those single-quotes around the URL. So in my example it looks like this:
And voila! You now have a tab that navigates directly to your view.