While not a complete list, I have personally used and recommend all of the below software and services.

Digital Photography and Image Editing

• Picasa^† – The defacto standard in Photo Organization.
• Adobe Photoshop Elements – Solid but have been thinking about moving to the freeware application Paint.Net

Security Applications

• KeePass Password Safe^† – Securely store all of your username’s and passwords.  AI Roboform is also good.
• Eset NOD32^† – Awesome anti-virus.  Just a little expensive if you have more than one computer.
• Norton Internet Security 2011† – If you have anything earlier than the 2009 version, get rid of it.
• Microsoft Security Essentials – A surprisingly good free anti-virus solution.

Utilities

• PowerArchiver^† – I switched to this from WinZip for handling compressed files (.ZIP) years ago.
• Notepad++^† – Great text editor.  If you don’t want to pay for it, try out
• SnagIt† - Great screen capture tool.

Back-up/Synchronization

• Windows Live Mesh^† (Formerly known as FolderShare and Windows Live Sync) – This app lets you keep files in sync between multiple machines.  Far more useful then Dropbox and it’s FREE.
• CrashPlan – Real-time backup of your files.  Free 2GB of backup space.

Communication

• Skype† - Keep in touch with friends and family with this video chat software.

Remote Desktop / Support

• TeamViewer† - When you need access to another computer or to give access of your computer to someone else, great set of tools.  LogMeIn is also a great alternative.  Both are free for personal use.

Internet Services

• Mint† - Keep track of your finances online.
• Windows Live Domains† - If you have your own domain, integrate Hotmail’s email and calendar with it and sync them across multiple devices with Hotmail’s ActiveSync capabilities.  Google Apps for Domains is a decent alternative as well.

(^†) Software I currently have installed on at least one of my two main systems.