John E. Gizis <jeg@pistol.caltech.edu>

[Table reflects most recent distances from Hipparcos.]
The most luminous star within 10 light-years is Sirius.
The most luminous star within 20 light-years is Sirius.
The most luminous star within 30 light-years is Vega.
The most luminous star within 40 light-years is Arcturus.
The most luminous star within 50 light-years is Arcturus.
The most luminous star within 60 light-years is Arcturus.
The most luminous star within 70 light-years is Aldebaran.
The most luminous star within 80 light-years is still Aldebaran.
The most luminous star within 100 light-years is still...Aldebaran.
The most luminous star within 1000 light-years is Rigel.  
  (Honorable mentions: Canopus, Hadar, gamma Velae, Antares, and
   Betelgeuse.) 
The most luminous star within 2000 light-years is Rigel.
The most luminous star in the whole Galaxy is *drum roll, please*
  .... Cygnus OB2 number 12, with an absolute magnitude around -10.
  (also known as VI Cygni No 12).

A table listing the nearest stars (within 12 light years) may be found
at http://www.ccnet.com/~galaxy/tab181.html.  The faintest star
within that distance is Giclas 51-15 with absolute visual magnitude
16.99 and spectral type M6.5.

Wielen et al. published the following as the local luminosity function
(total number of stars within 20 parsecs = 65 lightyears).  At the faint
end (abs. magnitude >12) this table is bit out of date and the numbers
are probably too high.  Everything from abs. magnitude 9 to 18 is
considered an M dwarf (shows TiO and other molecules) or a white dwarf.

abs. mag	Number
-1		1
0		4
1		14
2		24
3		43
4		78
5		108	Sun is here!
6		121
7		102
8		132
9		159
10		245
11		341
12		512
13		597
14		427
15		427
16		299
17		299
18		>16

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