MiKTeX -- an up-to-date implementation of TeX/LaTeX and related programs for Windows
http://miktex.org/

WinEdt -- a powerful and versatile text editor for Windows with a strong predisposition towards the creation of LaTeX documents
http://www.winedt.com/

XeTeX -- Unicode-based Tex:
http://xetex.sourceforge.net/

LyX -- An open source cross-platform word processor:
http://www.lyx.org/