I needed to know the database size of every database SharePoint 2010 uses. And I also needed information on the size that the database actually needs.
This gave me a little headache but, as always, PowerShell came to rescue me! With this little script you can get the databases, sorted from biggest to smallest, and also how much space they need (in MB)
Get-SPDatabase | Sort-Object disksizerequired -desc | Format-Table @{Label="DB Name"; Expression={$_.Name}}, @{Label="Size"; Expression={$_.disksizerequired/1024/1024}}