One true test that I’ve spoken about before of whether a website or webservice is important to you is whether it makes your top bookmarks (or in my case my links bar).

A big big big test for desktop applications is what starts by default when you start up your mac (or PC).

Like you, I try to minimise the number of apps that start up just to conserve memory and mindshare. So an app has to be crucial to start by default.

Here is my list;

• Quicksilver – I can’t start other things without it.
• Skype – my primary quick comms tool for voice and chat (my only chat tool really, other than a bit of gtalk
• Skitch – screen grabs, notes, funny stuff. I must use it 10 times a day and sometimes 100 times a day.
• OPML – it grabs pics from AP photographers and puts them on my desktop and screensaver, I love it, it’s like ad hoc news.

That’s it.

What’s your default and why?
What is your lungs? Your workhorse?