what are your "must have" Photoshop plugins (or filters)?

The only photoshop filter I regularly use is "blur" to frame the photo. By adjusting the contrast you can make it look like the film frame edge - you know that black border you get when you print a full frame negative.

(If I could post photos from my computer I would show you what I mean.)

Still, I'm interested in hearing what others are doing so I'll listen in.

Interesting boomer...ll have to give that a whirl next time Im playing around.
I know theres a great many plug ins that work wonders and everyone generally has their favorites but, I have really only played with most of them as Im still hanging onto the whole film idea. Since Ive always been a creative type though i have played around and I can see where many of them would be handy in the art world.
I do like some of the filters for watercolor, copypaper, brush strokes etc to see impressionistic variations on my photos.
Right now I just play with the border features for compiling composite pages.

I like the flaming pear "Blade Pro Plugins"
Eye Candy is also kool. In any event, here's just one sample, using these plugins in my attempt to "fool" mother nature:

Blur (Gaussian), Sharpen (Unsharp Mask) and to a lesser extent, Noise.

edit

The only filter I regularly use which doesn't already come w/ Photoshop is a colorize filter (not sure of the maker or the pack I originally stripped it from) which works MUCH better than Photoshop's Hue/Saturation-Colorize.

I have many dozens of plug-in packs on CD which I've never bothered to try out, but I have used KPT 3 & 5, as well as EyeCandy 3/4000 ( http://www.alienskin.com/ec4k/ec4000_main.html ) & Xenofex 2 ( http://www.alienskin.com/xx2/xx2_main.html ) in the past. All very cool...other than KPT3 which these days would be somewhat of a let down (it comes free with KPT5, though).

By the way, whatis1029, KPT 5, 6 & 7's (aka KPT Effects or KPT X) filters are available together in one bundle as KPT Collection ( http://www.corel.com/servlet/Satellite?pagename=Corel2/Products/Home&pid=1047022702225 ).

I just saw on Corel's web page that KPT Collection is currently offered (for a limited time, they say) free when purchasing Corel Painter 8. Not too shabby of a deal, considering Painter is already significantly better value than Photoshop (and Photoshop filters work with it).

IMO, really knowing how to use Photoshop's built-in filters, effects & tools well so you can get them to do what you want is much more useful & effective for most purposes than any 3rd-party filter pack ...but quick, high-quality special effects are certainly nice!