First, let me say - I love Lifehacker - I just wish it wasn’t so hard to keep up with - I’m out of commission for 2 days and I have 95 new things to read about 
Now what I’m really writing about.
View Rendered Source Chart is a Firefox plugin that lets your view the souce code of a page with the nesting in pretty colored boxes. Now if I could have a plugin for HTML-Kit that could do that same thing I’d be in heaven!
