winPenPack is a great way to download some of the most popular and highest rated open source software available.

The upside is that you might not want or like all of them, but it saves you the trouble of researching what is right and what isn't in the crowded open source utility market. You can efficiently manage or use any of the included programs via the winPenPack menu as you can see the screenshots below. It's small, simple and easy to use. winPenPack is a large download, but then again, that's a lot of software including graphics tools, drive utilities, PDF readers, zip utilities, RSS readers, email and so much more.

It also notifies you of any updates.

Some of the many apps included:

Documents management
SumatraPDF (.pdf reader)
X-LibreOffice (office suite, Microsoft Office open source alternative)
X-SciTE (text editor)

Personal Information management
X-ANote (sticky-notes)
X-Planner (project management tool)

Graphics
JPEGView (image viewer)
X-Gimp (image manager and elaboration)

Internet
X-FileZilla (FTP client)
X-Firefox (Internet browser)
X-MagicMailMonitor (mail monitor)
X-Pidgin (instant messenger with MSN, ICQ, AIM, and much more compatibility)
X-RSSOwl (RSS reader)
X-Thunderbird (e-mail client)

Multimedia
X-Audacity (audio editor)
X-CdrTools FrontEnd (CD/DVD burner)
X-VideoLAN (multimedia player)
X-xVideoServiceThief (tool for downloading your favorite video clips from a lot of video websites)

p2p - File sharing
X-DcPlusPlus (Direct Connect client)
X-HttpFileServer (file server, file sharing through web)
X-Mule (p2p)
X-qBittorrent (Bit Torrent client)

Security
X-ClamWin (antivirus)
X-Eraser (secure and programmable files and folder delete)
X-FreeOTFE (virtual disk creation protected by password)
X-KeePass (store and protect your passwords)

System
FreeFileSync (folder comparison and synchronization tool)
X-Abakt (backup tool)
X-DiskCleaner (search and delete for temporary and unvailing files)
X-JKDefrag (disk defragmentation tool)
X-StartupManager (a program that provides you the possibility to manage the Windows startup procedure)
X-Synkron (allows to synchronize two different hard drives or folders)
X-WinDirStat (disk usage statistics viewer)

Utilities
X-7Zip (file compressor/decompressor)
X-AstroGrep (alternative hard disk files and folders searcher)
X-CamStudio (it allows to capture desktop activity and save it as .avi file)
X-Lightscreen (it allows to saving and catalog screenshots in .png, .jpg and .bmp format)
X-muCommander (file manager)
X-StarDict (international dictionary software)
X-UniExtract (allows to extract/show the content of setup.exe files)

Tools
EjectUSB (utility to close all programs running from a specified drive and attempt ejection)

Libraries
FFmpeg
Ghostscript
GTK+ for Windows
LAME Encoder
Java Runtime Environment (Note: JRE is not included, but it will be downloaded and extracted through JavaGet)