What would people use for a website which will permit lots of listing to be placed. Think TM without the Ecommerce end.........

Ideally:
- Modern and easy to maintain
- Doesn't look like Sh** to the user
- Users can login via FB if they want (or create own login)
- Secure
- Simple CMS as well as permitting listings within specified categories
- Listings via a template if poss (within each category)
- Emails triggered if people reply to listings
Was thinking of a simple package before going custom if it takes off.
Have experience with vBulletin but wonder if there are better options out there.
Don't mind spending money (within reason).
Thanks