save2600

Yes, you can customize the "Unread Content" query, save it, and then make it the default.  To select which forums you want to see, click the "Content Types" menu, then "Topics", and then you can go through all the forums and select which ones you want to see.  Apply changes when you're done, make any other changes you want, then click "Save As New Stream".  You can then click the checkmark next to the stream name to set it as your default stream.

^Thanks Al!  (Check it out save2600!)  This is pretty cool and surprisingly easy.  For example, I just hit unread content, then made it for Content I posted in and Content of Members I follow.  I then labeled it Unread Content 2* and it shows up in my Activity Stream under Custom Streams (or something like that)...

*real original I know

Awesome, thank you Al! 

Labeled my stream as simply Unread Content Preferred.