Displaying which skin a user is using in postbit...just like here.
 

How can I go about adding the "Design: blue lagoon, fixed" in the postbit for every user?

That would be done using a custom query. To my knowlege vB doesn't support that by default.

But if you look on MySQL at the user table there is the column of styleid. You could fetch this data by putting a plugin on postbit_display_start.

Doesn't vb fetch all columns in the user table? If not, maybe i can edit the mysql and force it to instead of adding in a new query?

vB fetches most of the columns in the user table, but that doesn't include the name of the style, only the style they have set in their user cp (which may be different than the cookie that is set because they changed the style via the dropdown at the bottom of the page). There was a recent thread about this and the problems regarding it. You may want to try a search.