Right.
-Though I'm confused a bit by your oddly repeated use of the word "all."
?

As the OP, what I shoot primarily is indoor volleyball.  I needed a
camera that I could shoot at a fast enough shutter speed indoors to
freeze action with a 3.5 to 4 f-stop.  I'm using a 300D with hacked
firmware, shooting at ISO 3200 and noise correcting to my camera's
noise using Noise Ninja.  I use a Canon 28-105 3.5-4.5 US lens.
Occasionally I use a 50mm 1.8 Mk I when it's really dark.  I also
occasionally use a 70-210 3.5-4.5 US if I need the reach at a certain
venue.  In dark gyms, even at 3200, I'm shooting wide open at about
125th.  In well lit gyms, I still shoot 3200, stop down a bit, and take
advantage of the ability to shoot with more DOF.

My output is typically cropped and reduced to 800 px wide jpgs for a
team web site and 720 px wide jpgs used for an endo of season slide
show video.  I'm not printing at full resolution.

Gyms are typically lit with mercury vapor, and I set a custom WB for
the gym when I get there.  Saturday at the Car Wash fundraiser, I
simply forgot to reset the WB to auto until I had taken several photos.
A simple mistake.

Currently, I usually do pretty much all of my PP in iPhoto and it is
quick; simple cropping, a little histogram adjustment of exposure and
maybe a bit of sharpening.  Then the pics get cropped to 800 when I
export to an iPhoto-generated web page with thumbnails.

http://www.clearlakevolleyball.com

I tried a lot of methods of correction...  using color matching, using
the white point eyedropper in Curves, trying to match color histograms
in iPhoto...  What I eventually did was to examine the color
differences in the PS info window while hovering over my two reference
photos.  Based on the difference, I used Curves to move the Blue 80%
point down a bit and the Red 20% point up a bit until the result looked
OK.  I recorded this move as an Action and did the rest of the photos.

i must try out this grey card method...

Right, but the point others are making is that "resetting" it after the
fact is easier and more effective with RAW.  The difficulty reamins
figuring out exactly what to set it *to*.

BTW, I have issues with doing custom WB using grey card (or white, or
Expodisc, or whatever).  More with the whole *idea* of white balance.
Although the assumption is that our eyes adjust to the light and see
white as white (and other colors correspondingly) no matter the
lighting, this isn't how I perceive the world at all, and it rather goes
against centuries of convention in the art world.  When painting in a
traditional representational manner, one normally goes to some lengths
to portrary the color of the light *despite* the adjustment our eyes may
be making to fool us into removing the color cast.  The idea being that
a painting of a room lit by firelight *should* look very different from
one lit by an overcast sky through a window.  Most artists in this
tradition would say their are painting the light as much as they are
painting the scene.  So it always strikes me as ironic the lengths that
photographers will go through to remove all hint of the nature of the
light from their photographs.

Of course, I'm not saying that WB doesn't have it's place.  It is true
that our eyes will perceive more color in a room lit by incandescent
light than a camera will actually be able to record if the WB is not set
reasonably.  But then, "reasonably" need not mean set in such a way that
white truly looks white.  I wonder if it would be possible to devise a
surface that reflected light in such a way that is could be to set
custom WB in a manner that would still retain some of the character of
the light.  Of course, we could always carry around a set of biased
cards.  Set the WB using a cool-biased card when in warm light so the
camera will somewhat overshoot the color temperature (I think I have
that right), etc.  I gather Expodsic offers something like this.  But it
would be interesting to consider whether there was any way to do this
more auomatically.

---------------
Marc Sabatella
marc@outsideshore.com

Music, art,  & educational materials
Featuring "A Jazz Improvisation Primer"
http://www.outsideshore.com/

Sure, if you have time/opportunity, & the lighting mix doesn't change.