I'll add my voice to the chorus - #!/usr/bin/perl is best, even on windows systems since cygwin is a pretty common perl base under windows.

As for shebang, the American Heritage Dictionary says:

she·bang (shə-băng')
n. Slang.
A situation, organization, contrivance, or set of facts or things: organized and ran the whole shebang.

(Origin unknown.)

A one-size-fits-all word that pretty much covers the #! contrivance. Though they say "Origin unknown", I suspect it relates back to cannon, which make a slight "shh" sound as the touchhole is lit, followed in a few msec by "bang".