From left to right:
DNSCrypt: Encrypted DNS lookups (useful for public and corporate networks)
GasMask: Quick and easy access to edit your /etc/hosts file
Alfred: App launcher / Do By Searching
SSH Tunnel Manager: One-click start/stop for tunnels... again, useful for public and corporate networks (paired with FoxyProxy for Chrome)
Dropbox: Cloud-based file syncing
iTeleport Connect: Remote access for the iTeleport client (VNC-like screen sharing client on my iPhone)
Captured: Instantly uploads all the screenshots I take to tomfro.st, with optional editor and stuff, and puts that URL in my clipboard. That's where the above screenshots come from. (There's a free version in Ruby, but for a buck or two the version in the app store has WAY more features)
ColorSnapper: Quick and simple way to grab the hex code for any pixel on your screen, with magnifier.
Transmit: Just a helper for the desktop app
Splashtop Streamer: Remote access for Splashtop. Only because there's no iTeleport for my Android/WebOS tablet.
Display prefs built into mac
iStat Menus: The network graph, RAM meter, and CPU usage graphs are all from this. iStat Menus offers way more, but these are the ones I find useful.
Time Machine, Bluetooth (with low battery warning..), wifi, sound all built into Mac
iStat Menus: Clock/Calendar comes from there

. If you click on it you get this, which I couldn't live without:

...and then spotlight.