This singular application will change the way you use your mac. Once you wrap your head around it, you will understand it's power.
Check out this great post on getting started with Quicksilver:
Getting Started with Quicksilver
Possibly the coolest thing to hit Gmail, well...since Gmail itself.
Wraps a slick mac interface around Gmail, growl support, drag and drop attachments, sweet google talk integration, and take a screenshot it and have it immediately attached to your message.
My favorite instant messaging app for the mac. I used to be a Windows user, and I usually used Trillian or Gaim (now called Pidgin). Adium actually uses the libgaim library so it supports all your favorite IM accounts. My away message works great in conjunction with Twitterific (see below).
No doubt, the de-facto standard for web browsers. I use it because it's extensible with the browser plugins, like the Web Developer plugin that has become invaluable. And it manages to display websites quite beautifully, the way it was intended.
This is definitely my geek-out, fantastico favorite editor of all time. You can do so much with it, it's sick. I love apps that are really rich in keyboard shortcuts and clever ways of doing things, and this app definitely is tops in these areas; I'm always learning something new and cool to do with it.
Obviously this is a no-brainer. I love Adobe Photoshop. Since CS3 has came out, it has really been a huge improvement in my workflow. The interface seems much more responsive (universal binary for those Intel mac users), and it seems more "mac-ish", if that makes sense. I really like how they added the fade effects when you drag panels around, and how when you resize your image your interface responds accordingly, showing you more or less of the interface as you need it. This is a fantastic improvement in usability I think. That's just one of the many new features, one of my favorite being the Quick select tool. See more info about Adobe Photoshop CS3 here.
This new application from Adobe has a pretty slick interface, and I'm a sucker for those. I think Adobe sums it up better than I can:
"New Adobe Photoshop Lightroom software is the professional photographer's essential toolbox, providing one easy application for managing, adjusting, and presenting large volumes of digital photographs so you can spend less time in front of the computer and more time behind the lens."
If you do FTP on the mac, then you need to use Transmit. It's made by the great guys at Panic.com
This is a great app that works in conjunction with Twitter.com, to allow you to post tweets, and to receive your friends' tweets. It uses the API, that Twitter provides. And if you're still not sure what Twitter is, check out my post Twitter: An Overview.
Ok, TV on your computer. Nothing new there, but this app is very cool in that it's free, and it works very very well with a new Macbook and it's handy little remote control. How they made this work effectively with the remote, I"m not sure, but I certainly appreciate it. They've gotten quite big recently, they are in beta, but I hope the service maintains it's quality it has. Basically the gist is that, it's a P2P network that supports the downloading, which is pretty cool. I'm also very excited about Adult Swim signing on as one of their channel providers. So far these guys have impressed me a lot with their quality website, and delivery of video in a gorgeous interface over the web.