Quicksilver – absolutely essential. Once you learn to use Quicksilver to launch your apps and you’ll never dig through the Applications folder in the finder again. And that’s just the beginning.  Find out more about how to use Quicksilver by watching Episode12 or Episode 17 of Macbreak.

Flip4mac – Nobody that owns a Mac really wants anything that has anything to do with Microsoft on their machine.  Thankfully this app isn’t made by the boys in Redmond so it works really well.  This app makes QuickTime work with Windows Media files – a video format which is used by many, many Web sites.

Perian – the Swiss Army Knife for QuickTime – meaning it’ll make QuickTime play files that it normally wouldn’t, like FLV.  What this means is that you can download flash videos from Google Video & YouTube and actually be able to use them almost anywhere you can use QuickTime.

Firefox – Safari is a great, fast browser, but Firefox needs to be on your Mac.  I use it as my everyday browser and with plugins for web development, del.icio.us bookmarks and ad blockers it makes browsing productive.

Cyberduck – I know a lot of Mac users love Panic’s Transmit application for FTP but I’m a big fan of Cyberduck.  It works consistently and plays really nice with many of the other apps I use day-to-day.

Growl – Growl is a system notification app. It alerts you to various events that are happening on your machine.  I use it to alert me to new mail and inform me of ftp upload completion (it plays really nice with Cyberduck, Mail.app, Adium, iPhoto (w/FlickrExport) and NetNewsWire

NetNewsWire – NetNewsWire is an awesome RSS reader. I use it to keep up on the news sites and blogs I read. It uses NewsGator to sync what I have and have not read between the various machines I use.

SuperDuper! – SuperDuper! is a painless backup & recovery software.  During the mess that was the upgrade to OS X 10.5 I used SuperDuper to backup and restore my system more times than I wish to remember.  It creates a disk image that  is bootable from any firewire drive.  It’s basic functions are free but it’s well worth the money for the extended functionality.

Handbrake – A DVD, ahem, backup tool. You know, for all those DVD’s you have that you’d like to have digital copies of so you can, um, watch them on your computer, without actually having to use the discs.  It’s really great if you have an AppleTV, like me.

Adium – Adium is a multi-protocol chat client- meaning it works with AIM, Google Talk & Yahoo! and many more. It can be buggy, but it’s great for having one place to chat with everyone.

Widgets

Technically these aren’t really applications, maybe web apps, but most are just graphics with javascript, HTML and CSS.  I don’t use them a ton but these two have found a special place on my Macs.

• Delivery Status Widget – works with all kinds of shippers and notifies you of updates via Growl
• Jared: The Butcher of Song – every once in a while you need to be serenaded – this is not for those times.

What about you?

Do you have any apps that are must haves on all your Macs? Have a widget you can’t live without? Drop me a comment and let me know.