For most situations, you can use either a GFCI outlet as the
	first device on the circuit, or you can install a breaker with
	a built-in GFCI.  The former is generally preferred, since GFCI
	breakers are quite expensive.  For example, an ordinary GE
	breaker costs ~US$5; the GFCI model costs ~US$35.  There is one
	major exception:  if you need to protect a ``multi-wire branch
	circuit'' (two or more circuits sharing a common neutral wire),
	such as a Canadian-style kitchen circuit, you'll need a
	multi-pole GFCI breaker.  Unfortunately, these are expensive;
	the cost can range into the hundreds of dollars, depending on
	what brand of panel box you have.  But if you must protect such
	a circuit (say, for a pool heater), you have no choice.

	One more caveat -- GFCI outlets are bulky.  You may want to use
	an oversize box when installing them.  On second thought, use
	large (actually deep) boxes everywhere.  You'll thank yourself
	for it.

	Incidentally, if you're installing a GFCI to ensure that one
	specific outlet is protected (such as a bathroom), you don't
	really have to go to all of the trouble to find the first
	outlet in the circuit, you could simply find the first outlet
	in the bathroom, and not GFCI anything upstream of it.  But
	protecting the whole circuit is preferred.

	When you install a GFCI, it's a good idea to use the little
	"ground fault protected" stickers that come with it and mark
	the outlets downstream of the GFCI.  You can figure out which
	outlets are "downstream", simply by tripping the GFCI with the
	test button and see which outlets are dead.

	Note that the labels are mandatory for GFCI-protected-but-ungrounded
	three prong outlets according to the NEC.