I've worked with a broad spectrum of organizations.
Here's some from the past several years.

Technology

AMCC
Apple
Asymtek
Brooktree
Elgar
General Dynamics
Hewlett-Packard
Hexfet America
IBM
IXC Communications
marchFIRST
NCR
Northern Telecom
PrimeCo
Puritan Bennett
Sea West
Sybase
Teletrac
TriTech
Verizon

Public Sector

California Department of Fish and Game
California Department of Justice
Canadian Federal Government
City of Berkeley
City of Brentwood
City of Carlsbad
City of Del Mar
City of Encinitas
City of Escondido
City of Lake Elsinore
City of Lynwood
City of National City
City of Oceanside
City of Oxnard
City of Sacramento
City of Salinas
City of San Diego
City of Santee
City of Ventura
Helix Water District
Internal Revenue Service
Mission Springs Water District
Mission Springs Water District
Orange County Sanitation District
Otay Water District
Port of Los Angeles
Rincon Water District
San Diego County
San Diego County District Attorney
San Diego Housing Commission
Santa Clara Valley Water District
Sante Fe Water District
Vista Irrigation District

Healthcare

Community Care Network
Palomar-Pomerado Health District
UCSD Medical Center

Service-Oriented Organizations

ACS (Architecture)
Boston Consulting Group
Dudek (Engineering)
Morrison & Foerster (Legal)
National Dispatch Center (Call Center)
Salk Institute (Scientific Research)
United Methodist Church 

Schools and Universities

California State University San Marcos
Encinitas School District
National University
San Diego City Schools
San Diego State University
Southern Methodist University
University of California San Diego