This plugin by Andy Potanin is not a “collection” of plugins, but one full suite. You will not have to download and match together a plethora of other plugins, in the hopes of them working well together, to have all the features you need.
The only requirement, you have to use WordPress 3.0.
Seamless Integration with WordPress 3.0
Custom ‘property types’ and templates for complete customization.
Built-in gallery and thumbnail generator.
Custom attributes are easily added or removed.
Property search by attributes.
Customize invoice notification emails invoice, or use templates.
SEO friendly URLs generated for every property, following the WordPress format.
Widget for Featured Properties.
Widget for Search.
Widget for Gallery.
Requires WordPress 3.0
Plugin homepage with info and screenshots: http://twincitiestech.com/plugins/wp-property/