Mac provides you various ways to display your Date & Time. You can either display it to cling on your menu bar or to snap on your Finder Window.
Cling to Menu Bar
Snap on Finder Window
You change change to one of those types of display by going to QuickSilver >
dtimepref. Then under the Clock tab you can set the specification of your clock displayed.
You can also set up your transparency inside there.