GMail has a very useful undocumented shortcut which allows you to delete mails. Select the required mails in the list and press # key (shift+3) and all the selected message will move to Deleted Items. I tried this shortcut on Microsoft Internet Explorer & Firefox browsers and it worked.
GMail shortcuts work only if Keyboard Shortcuts option is switched on. Follow these steps to enable shortcuts in GMail
- Click on Settings link
- Identify Keyboard shortcuts option available in the General Setting tab
- Choose Keyboard shortcuts on
Also read the article GMail - The Best Mail Service With Least Storage Space to know storage capacity comparison of major e-mail services.