A) What you are looking for is a Trimble GeoXT or GeoXM.  It is a handheld
GPS unit/PDA.  You can install ArcPad on the unit and instantly make GIS
shapefiles while out in the field.  This unit, which is very bulky, has
great potential.  The problem: trying to obtain and maintain a signal,
especially within wooded areas.

B)The Garmin eTrex Vista, although does not have the same features as the
Trimble, is a great little GPS unit.  It has 3-5 m accuracy, which is the
same as the Trimble unit above.  It stores hundreds of waypoints and a few
track and route logs, which can then be downloaded using a free program
into ArcView 3x.  It is small and compact (smaller than my hand);
therefore, easy to carry--wear it around your neck, stick it in your field
vest/jacket, pants pocket, backpack. The great thing about the Garmin
eTrex Vista or any in the Garmin eTrex family is that they WORK.  Signals
are easily obtained and maintained in a variety of settings, unlike with
the Trimble unit.  Plus, this little piece of technology is under $300,
while the Trimble unit costs closer to $5000.