Need more space for your mails? Gmail has got multiple inboxes for you! Google just added a new Labs feature called Multiple inboxes which allows you to do just what it says - have multiple inboxes. You can have multiple frames in the inbox view with filtered content in each inbox. The main pane can show all the inbox content and the other panes can show filtered content like Starred mails, Drafts, Mails with a specific label, etc.
The main pane on the left has the complete inbox, the top pane on the right has the starred messages and the one below has messages labelled “Blog reports”.
You can customize the contents by going to Settings -> Multiple inboxes, and entering the view you want. For example: is:starred is:unread has:attachment label:something
More on the Official Gmail Blog.