Any hoo, I was also wondering, do all of the pics have a serial out
    command (like pbasic's serout), because if I get the cheaper one, it
    will only program 18 pin chips, which according to Digi-Key, none of
    them include these serial features. I HAVE to have that feature.

NONE of the PICs have a "serial out" command.  Some of them have an
internal peripheral called a UART that makes it somewhat easier and
potentially less "cpu intensive" to implement such a function, and ALL
of the PICs can have routines equivilent to "serial out" WRITTEN for
them in assembler or (compiled) C or Basic or whatever.  There's a
sample routine in the PIC applications guide, and there have been
several such routines posted here in the past.  Some compilers may
already provide such a function.

IMHO, Parallax pushed the embedded world in a new direction when they
allowed SEROUT to work on any pin of the stamp.  Previously, async
serial peripherals (1 wire + GND) were next to unheard of.  Now all
sorts of interesting devices are popping up all over - LCD displays,
memorys, sensors, servo drivers, etc, etc, etc.  Neat stuff, especially
since it allows quite a bit of new flexability on LARGER computers
(Wanna guess how much it would cost to put a simple LCD display on a
PC-type platform before products like the PIC-based "serial backpacks"
came along?)


    Then once I get a programmer, what pic should I use?  I am somewhat
    attracted to the ones with the A/D converters on them just because I use
    a lot of sensors in my projects (I.E. hall effect transducers, mics,
    this neat-o thing called a pulse amplifier, I rigged up one of the
    school's pH probe to my calc set up, etc.).

The flash based parts are the only ones that are inexpensive in their
reprogrammable versions.  While they don't have built-in A-D converters,
you can use algorithms similar to those used in the basic stamp to do
some sorts of A-D measurements.  It sounds like some of the stuff you
are interested in might require more sensitive/accurate A-Ds anyway, not
to mention carefully designed analog circuitry...

BillW