The site hierarchy and taxonomy could benefit by restructuring.
Some navigation improvements:
Sidebar should contain all widgets relevant for the area in which they pertain. e.g.. In the albums section of the site, all pages should contain the albums widget. Album widget should have a "Create New" link to add Albums on the fly and not only when Uploading/editing a photo.
Items within the main section of the page that are useful to all pages within the relevant area of the site should be moved to the sidebar. e.g.. The upload photos link should be moved to the sidebar and be made available on every page in the albums section. Currently, several clicks are needed to go from editing a current photo and uploading a new one. This could be minimized to a single click.
Edit buttons should be made available on every page that is editable. e.g.. An edit button on the profile page for quick revisions after viewing own profile.
The sidebar can be used to condense areas of the site which have multiple pages with minimal content on them. e.g.. The Events section could contain the form for adding a new event in the sidebar of the main page. The calendar can be moved to the top of the sidebar and the form made available beneath, either open or collapsed and opened via the Add New Event link.
Tabs (buttons on TestBubble) should be available throughout the relevant areas of the site for easy navigation. This includes secondary pages. e.g.. Clicking on Send Message takes you to the message creation form. The tabs for inbox, outbox and Create New Message are missing.
Autocomplete text fields rather than select lists would be easier to use in selecting recipients. This is particularly important for users with hundreds or even thousands of friends. Another option for spaces such the as Create New Message form could be an address book type of interface in the sidebar which is currently empty.
When possible, use ajax to change views rather than reloading the page. e.g.. moving through the calendar months.