iTeXMac is a teTeX front end, a text editor dedicated to TeX and a PDF Viewer
Features:
iTeXMac has
syntax coloring and much more
customizable macros
customizable key binding
iTeXMac can
do anything teTeX can (with a little effort)
use LaTeX, ConTeXt, MetaPost, amsTeX (just the same as above!)
use your favorite external Text editor
use your favorite external PDF viewer
use your favorite external DVI viewer
view standard graphic files
render DVI, PS and EPS files
navigate from errors to source, source to output and conversely (quite)
navigate from DVI to source, source to DVI and conversely