A collection of a few of the tools we use at OneButton on a day to day basis:
Accountancy
Neat receipts [$139] An accountancy app coupled with a receipt/doc/card scanner
Collaboration
Google apps [free] Hosted office suite
Slideshare [free] hosted powerpoint sharing
DimDim [free/$] Screen share collaboration software
http://www.dimdim.com/products/dimdim-video-tour.html
Lovelycharts [free] online hosted flowchart application
http://lovelycharts.com/index.php?page=tour
Operational
37 signals [$12/mo+] basecamp and highrise, project and contact management
busy sync [$40] universal calendar synchronization between google calendar/iCal
Netsuite [$120/mo++] Full company wide hosted Enterprise Resource Planning software
Time Capsule [$300/500GB] Automatic backup solution + WiFi Router with guest networking
http://www.apple.com/timecapsule/
mobileMe [$100/yr] apple's version of exchange. Contact/ calendar sync mobile disk access
WordPress [free/$] online blog creation
http://en.wordpress.com/features/
Google Analytics [free] Domain statistics tracking website traffic monitoring
https://www.google.com/analytics
Telecom
Virtual: Virtual PBX [$40/mo+] Virtual PBX phone routing system
Real: Packet 8 [$99/phone, $40/mo] Routes calls to any IP phone.
Grand Central [free] One number that rings all your phones
Legal
TechStars legal forms [free] All the basic forms you could ever want - from The Foundry
http://www.techstars.org/2009/02/07/techstars-model-seed-funding-documents/
PR/Marketing
twitter [free] Best PR Available (@comcastcares, @delloutlet)
TweetDeck [free] twitter monioring tool. Take it a step further with radian6 [$$$] readwriteweb
Development
Github [free] parallel development through social coding
