Lets use this wiki page to start the base module list. These modules should be ones that every B&B just can't do without.
Modules to add
TinyMCE - For easy editing
image - Image support
IMCE - Image integration with TinyMCE
WebForm - Useful for creating more custom contact form
PathAuto - For good SEO practice (Token module needs to come along too)
Node Words - Set meta tags for your pages (Good for SEO)
Others I have used include Recipe module, and poormanscron.
suggestions welcome...
Themes
suggestions welcome...
B&B specific modules
custom node modules, reservation engines, availability trackers suggestions welcome...
Availability Calendars - Show daily availability using calendars per node