Okay, I just figured out a neat trick.
Add ~/Library/Printers/ to your Quicksilver catalog.
Select any document you want to print with Quicksilver (b42 tip: select anything and hit command-escape).
Tab into “action” and select “open with…” and tab into the third field.
Type the name of your printer. Hit Enter.
Watch your file come out of the printer, and get right back to what you were doing.

(With a few clever preference modifications (such as changing the spacebar behavior to “Jump to Argument Field” under “Command”), I’ve gotten this down to select SPACE {$printername} ENTER.)
The point of this, and every other Quicksilver trick, hack, or silly widget, is that it lends itself to easy habituation, and thus becomes invisible.
In english, that means that after using any particular action a couple of times, it disappears into the background of conscious action, and becomes a habitual gesture… much like downshifting to second gear before turning your car onto another street. It doesn’t require a lot of conscious monitoring or decision making, and it can safely be done blindly, without your having to shift mental gears. So to speak.
Many people don’t see the point of things like this trick, because this is extra, widgety stuff that adds on to Quicksilver. It doesn’t become helpful until you’ve gotten into the thoughtless habit of using it for dozens or hundreds of tiny operations a day. Once you begin to take it for granted that you email someone by typing their name without worrying about whether Mail.app is even running, or that you open a new web browser window directly to the page you wanted with a couple of unconscious keystroke gestures, being able to print a file the same way isn’t a big deal.
But I have. And it’s one more computer operation that I can forget about, because it’s become invisible. It made me happy, so I shared.
Got any other little add-ons to the Quicksilver zeitgeist that make you happy? Share.