Constant Contact - can't find a better customer email subscription service
GotVMail - 800 service for phone service with 800 number, hunt groups, and custom greetings
Prominic - Remotely hosted Domino servers - with full configuration and installation.
Entellium - CRM with strong customer service and nice user interface
Ad Words - The best marketing dollars that we spend
Mailstreet - Remotely hosted exchange and sharepoint (ahhh...it's just great having someone else worry about mail availability and uptime)
What are the common themes? Well, in all cases, someone else is focusing on delivering a specific service at a great price. They focus on their core competency (like email hosting) and then we spend more time building software and less time managing operational services (e.g phone system, mail, CRM).