The following links are to companies I can recommend:

APLD--Association of Professional Landscape Designers:
National certifying organization for landscape professionals.
www.apld.com

Sonoran Gardens Landscaping Inc.
Full service landscape installation
          www.sonorangardensinc.com

Santa Rita Landscaping Inc.
Full service landscape installation
           www.santaritalandscaping.com

Pottery Blowout
Great selection of pots for plants or water features. 
            www.potteryblowout.com

Today's Patio
Outdoor tables, chairs, bar stools, propane fire pits, umbrellas, etc.
             www.todayspatio.com

The Contained Gardener
Creative containers and raised beds, installed and maintained.
             www.thecontainedgardener.com

Mesquite Valley Growers
Great plants of all sorts; trees to groundcovers, tropical and native.
              (no website address available)

Tohono Chul Park
A great place to go for inspiration.  Also a nice place for lunch!
              www.tohonochulpark.org

Tucson Botanical Gardens
A great place to see good combinations of native plants.  Good classes too.
              www.tucsonbotanical.org

Trees for Tucson
$8 native trees, subsidized by TEP.  Must be planted within 15' of your home on the east, south or west side of your yard.  A GREAT bargain!
               www.tucsonaz.gov/tcb/tft/index.html#shade

Mexican Tile & Stone Company
Amazing selection of ceramic tiles, hand painted tiles, all kinds of stone tile. 
                www.mexicantileandstone.com

The RBDI Group
Graphic design, website design, computer services, photographic services
....if you like my website, they designed it! 
               www.rbdi.net