Sensible defaults for Mac OS X Lion

.osx

# Enable full keyboard access for all controls (e.g. enable Tab in modal dialogs)
defaults write NSGlobalDomain AppleKeyboardUIMode -int 3

# Enable the 2D Dock
defaults write com.apple.dock no-glass -bool true

# Make Dock icons of hidden applications translucent
defaults write com.apple.dock showhidden -bool true

# Disable menu bar transparency
defaults write NSGlobalDomain AppleEnableMenuBarTransparency -bool false

# Always show scrollbars
defaults write NSGlobalDomain AppleShowScrollBars -string "Always"

# Expand save panel by default
defaults write NSGlobalDomain NSNavPanelExpandedStateForSaveMode -bool true

# Expand print panel by default
defaults write NSGlobalDomain PMPrintingExpandedStateForPrint -bool true

# Disable the “Are you sure you want to open this application?” dialog
defaults write com.apple.LaunchServices LSQuarantine -bool false

# Disable shadow in screenshots
defaults write com.apple.screencapture disable-shadow -bool true

# Enable highlight hover effect for the grid view of a stack (Dock)
defaults write com.apple.dock mouse-over-hilte-stack -bool true

# Enable spring loading for all Dock items
defaults write enable-spring-load-actions-on-all-items -bool true

# Show indicator lights for open applications in the Dock
defaults write com.apple.dock show-process-indicators -bool true

# Don’t animate opening applications from the Dock
defaults write com.apple.dock launchanim -bool false

# Disable press-and-hold for keys in favor of key repeat
defaults write NSGlobalDomain ApplePressAndHoldEnabled -bool false

# Disable auto-correct
defaults write NSGlobalDomain NSAutomaticSpellingCorrectionEnabled -bool false

# Disable window animations
defaults write NSGlobalDomain NSAutomaticWindowAnimationsEnabled -bool false

# Enable AirDrop over Ethernet and on unsupported Macs running Lion
defaults write com.apple.NetworkBrowser BrowseAllInterfaces -bool true

# Disable disk image verification
defaults write com.apple.frameworks.diskimages skip-verify -bool true
defaults write com.apple.frameworks.diskimages skip-verify-locked -bool true
defaults write com.apple.frameworks.diskimages skip-verify-remote -bool true

# Automatically open a new Finder window when a volume is mounted
defaults write com.apple.frameworks.diskimages auto-open-ro-root -bool true
defaults write com.apple.frameworks.diskimages auto-open-rw-root -bool true

# Display full POSIX path as Finder window title
defaults write com.apple.finder _FXShowPosixPathInTitle -bool true

# Increase window resize speed for Cocoa applications
defaults write NSGlobalDomain NSWindowResizeTime -float 0.001

# Avoid creating .DS_Store files on network volumes
defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true

# Disable Safari’s thumbnail cache for History and Top Sites
defaults write com.apple.Safari DebugSnapshotsUpdatePolicy -int 2

# Enable Safari’s debug menu
defaults write com.apple.Safari IncludeDebugMenu -bool true

# Remove useless icons from Safari’s bookmarks bar
defaults write com.apple.Safari ProxiesInBookmarksBar "()"

# Disable send and reply animations in Mail.app
defaults write com.apple.Mail DisableReplyAnimations -bool true
defaults write com.apple.Mail DisableSendAnimations -bool true

# Disable Resume system-wide
defaults write NSGlobalDomain NSQuitAlwaysKeepsWindows -bool false

# Enable Dashboard dev mode (allows keeping widgets on the desktop)
defaults write com.apple.dashboard devmode -bool true

# Reset Launchpad
rm ~/Library/Application\ Support/Dock/*.db

# Show the ~/Library folder
chflags nohidden ~/Library

# Disable local Time Machine backups
sudo tmutil disablelocal

# Kill affected applications
for app in Safari Finder Dock Mail; do killall "$app"; done

# Fix for the ancient UTF-8 bug in QuickLook (http://mths.be/bbo)
echo "0x08000100:0" > ~/.CFUserTextEncoding

I honestly don't know. I saw these defaults yesterday on someone's GitHub repository and copied it to this Gist for future reference. I haven't played much with these settings yet. If I spot a way to do so, I'll let you know.