1. This may be obvious but as of the latest version, you don't gain much from a corporate email program like Entourage. I use Apple Mail, with IMAP and Google Apps for Your Domain. One account has 3.8GB of email and another has 4.1GB, according to Google. It scales fine and stays in sync across devices. Plus Address Book links to Google Contacts, and iCal links to Google Calendar.

2. I prefer MagiCal (http://www.charcoaldesign.co.uk/magical) rather than Eigenclock as it includes options to put "yyyy-mm-dd [day] hh:mm:ss" by the Spotlight icon, with [day] clickable for the calendar.

3. I like SpeakTime (http://www.mecanisme.net/software/speaktime/) for putting a row of glance-able analog clocks at the lower left of my screen (semi-transparent so they look like part of the background) to be aware of alternate time zones.

4. I use Skitch (http://www.skitch.com) for screengrabs with annotations to share with colleagues/clients.

5. I use Serverskine (http://www.serverskine.com/) to keep track of server logins.

6. I use Foxmarks (http://www.foxmarks.com/) to keep bookmarks in sync across all browsers and computers.

I don't use QuickSilver, Spotlight gets the job done.

I'd also recommend the following paid apps depending on your needs:

1. iWork '09 (Pages, Numbers, Keynote) for all office apps needs with MS Office 03-07 compatibility. It's worth the $79 for the polish and usability. The "free" alternative will cost more in the long run.

2. OmniGraffle Pro for diagramming with Visio (even Visio binary file) compatibility.

3. OmniPlan for MS Project compatibility.

4. Coda for text based web development. (Yes, TextMate is in my dock. But so is Coda.)

5. 1Password for credentials management across browsers and computers

6. Things for "GTD" methodology (or OmniFocus for more features)

For major presentations, I'd also recommend looking at some of the commercial themes available. E.g. keynotepro

Apple-Shift-3 captures the entire screen.

Apple-Shift-4 lets you select an area to capture.

Apple-Shift-4 then Space captures a window that you select.

I don't personally use GrabUp or Skitch, so I can't comment on what they add.

Skitch adds annotations and sharing with almost the same simplicity as the built-in keystrokes. I typically use "⌘-Shift-4, Space" as well, when using the screens in my own work, but not when annotating or sharing.

For quick annotations, pointing things out, highlighting things, and instantly pasting someone a viewable image URL (with one click to capture, and one click to share), Skitch is tough to beat.

I used to use transmission, but then I started using uTorrent, which I find has better performance. http://www.utorrent.com

I really wish it wasn't the case, but Quicksilver seems to have had its run and no one is stepping up to the plate to preserve it.

Most everything else you list is awesome though (although I think Evernote is far from essential and I'm not sure "free" is the right word for it ;)

Also, I haven't had any problems with crashes or anything like that... works great here.

Usually it's as fast as LaunchBar except for the very first time it is used. It has a reputation of being slow from 10.4 that is no longer justified.

The original author has been hired by google and is working on google quicksearch box http://qsb-mac.googlecode.com

Hmm. Sounds familiar. Or it would if I were still eating your company's dog food.

Doesn't do IRC. In fact I've been unable to find any osX chat client that does IRC and IM.

Anyone found a solution?

That said, if you're looking to access IRC easily, that's the way to go.

Use irssi or xchat.

How is Mibbit for idiots? It lets me give URLs to people who want to join chat rooms, so if I want to invite somebody to a channel I don't have to say "Download this, then fill out this and this and this in the boxes," I can just link them and they click it and they're in. I can style it to my heart's desire. It's customizable as anything. It supports tabs for multiple rooms at once.

I do use Colloquy or irssi when at home, though.