There are lots of books on portraits, and everybody seems to have their own
favorite techniques.  I like to use an 85mm 1.8 focused on the eyes but
fairly wide open to blur the background.  I also like to use natural window
light and shoot indoors, although I'm getting the hang of using a fill flash
for outdoor work.  No filters or gimmicks of any kind.  No multiple lighting
systems.

The SB800 will do a great job outdoors, even in daylight, and I doubt you
will need anything more than the kit lens, unless you want a shallow depth
of field.  Can't see why you would want any filters, although a polarizer is
great for landscapes.

I'm no pro, but generally, I don't think you'll need special filters
for this. Do use the SB800 for fill-flash, even in bright sunny
conditions - practice first and check the EXIF data when you review
the results to see what works. Keep the lens towards the 70mm end and
step-back for portrait work.

Usually, I'd set the flash EV to -0.7 or -1.0 when filling in
otherwise good light. Drop it further based on the LCD preview results
- your distance has a large affect on this. Also if using direct-flash
to fill (eg, no bouncing) use the diffuser that comes with it.

Buy a large white foam-core board and use it as a reflector,
positioned somewhere in the lower arc of the subject. Position it so
it illuminates some of the worst shadow areas.

The SB800 works well in bounce-flash mode if indoors and either a
white wall or ceiling is available. If bouncing from the ceiling, pull
out the little white catch-light card, so it throws some light
forwards for the eyes to reflect.

Only use slow sync mode if you are trying to capture ambient light in
low-light conditions (or some movement, such as a kid waving a
sparkler) - I'd suggest rear-slow for this. This does bring it's own
set of problems for good results, the need to keep the subject and
camera still is one of them.

Do some shots with a tripod, and others where you get onto the floor
or onto a short ladder to add some intersest/dynamics to the photo.

There is no one right-way. Lots of things work, some things work for
some faces, and not for others. Harsh single-source lighting can be
good for men, soft multi-source lighting better for women. But one's
own opinion has the greatest impact to which is the best way for a
given subject/situation.

Girls with long hair can be backlight (eg, at sunset put their head so
it obscures the sun, now hit them with some fill-flash and dial it
down until the balance looks good on the LCD). I took some cool
portraits of my kid yesterday at the fireworks pre-show by laying down
on the floor and shooting directly up towards the sky. Evening
lighting plus some flash is cool.

For really moody lighting, use a fairly dark room and put the SB800
into slave mode, off to one side of the subject, either bouncing on a
wall or small white card - or even facing directly at the subject. The
closer you put the SB800 and the less diffused/bouncing the source of
light, the harsher the shadows will be on the face.

Just some ideas - the most important thing is to play a lot, and
investigate the successes as to why they worked.

--
Owamanga!
http://www.pbase.com/owamanga

Now that's an image.  I think your caution is justified.  Mounting a
person on top of a filter is likely to cause severe vignetting.  :-)

Randy W. Sims asked:

"Well, here I am, Baby.  What were your other two wishes?"

oh...

On Mon, 04 Jul 2005 22:46:19 -0400, in
<S-2dncarM6bgaVTfRVn_vg@giganews.com>, "Randy W. Sims"
<RandyS@ThePierianSpring.org> said:

I can't think of a single reason to ever use a filter when shooting
people with a DSLR. Correcting colour casts is trivial to do when you're
processing your photos on your computer, & colour-correction is pretty
much the standard reason for using filters when shooting 'people shots'.
Just about any problem you're likely to run into when photographing
people is going to come down to lighting, & whole books have been
written on that topic. Spend some time reading some of the websites that
Owamanga recommended in his reply to you, & you'll probably find it a
lot easier to get good results.

You don't get instant good, or even better, pictures by buying filters,
anymore than you can run a filter in photoshop and get 'art.'   OTOH, they
probably won't hurt much.

google joseph zeltsman for an excellent tutorial on posing and lighting,
though the samples are very dated looking the info is first rate as it
articulates quite well the WHY of posing and lighting a particular face this
way instead of that, it teaches you a logical system of making decisions.