I do not intend to be "fair" or justify these. This is my biased list.

Physics/Math

Vector Algebra
Geometric Algebra, also known as Clifford Algebras.
Probability & Statistics
Bayesian
E&M units
Heaviside-Lorentz
Number base
Balanced base three or nine

CS

Programming Style
Declarative & Functional
Acceptable Languages include:
C, Haskell, Sather (sadly defunct), Sisal, Python, and Common Lisp.
Operating Systems
Unix-alikes
parallelism models
CSP. Down with unrestricted threads.
hardware microarchitecture
explicitly synchronized / asynchronous / CSP
shell
zsh
window manager
ion
Automated builds
cook
fmt
par
text encodings
utf-8
file synchronization
unison
global network file system
sfs -- self-certifying file system
mail client
mutt

The right thing, useable, but not quite good enough (yet):

version control
darcs -- scaling issues, robustness
usenet
slrn -- charset handling. Silly macro language.
dependency tracking for builds
autodep -- good for what it does, but doesn't quite do what I want.

network services

bookmarks -- del.icio.us
save, categorize & share tasty bookmarks.
mailing lists
gmane -- mail to news done right, plus a good web interface.