in reverse alphabetical order:
Visible Image - great for cool and unique stamps
STAMPlorations - my absolute favourite place for stamps that inspire imagination, ARTplorations stencils/masks and CUTplorations Thin Metal Dies. Best of all they do have a flat international shipping rate, and, if you're a member of their STAMP CLUB, you're in for a host of other benefits too.
Stampin'UP! my personal demonstrator is Katie - Jane Gregory. I usually order through her mum Dianne.
The Ribbon Girl - great for all things ribbon and embellies
Lily of the Valley - great for cute stamps
Lavinia Stamps - Fab mystical and Fairy stamps
Lacy Sunshine - great for cute and girlie digital images
docrafts - great range of stamps, papers, tools and embellishments - seek out your local craft shop, they are sure to stock some of their products or try your local garden centre with a craft shop attached.
Dies to Die for - great selection of cutting dies