There's a hidden setting for the Dock that will show pop-up notifications of which iTunes track is playing, a little like Growl.
First, quit iTunes if it's open, then open a Terminal window and type the following:
defaults write com.apple.dock itunes-notifications -bool TRUE;killall Dock
Then start iTunes and try playing a track. Neat, eh? The pop-up fades away after a few seconds. To add the iTunes icon to the pop-up window, type the following into a Terminal window:
defaults write com.apple.dock notification-always-show-image -bool TRUE;killall Dock
To deactivate the pop-up at a later date, quit iTunes again, then open a Terminal window and type the following two lines:
defaults delete com.apple.dock itunes-notifications
defaults delete com.apple.dock notification-always-show-image;killall Dock
My theory is that these pop-ups hint at either a forthcoming notification system (maybe in OS X 10.8), or it's a legacy of a notification system that Apple decided to abandon. But it's easily to imagine a similar system working with Mail, showing notifications of incoming mail. In addition to the preference keys mentioned above, I found various other keys relating to the height and length of the pop-up bubble. Whoever designed this clearly intended it to be tweakable.
In the past, saving with certain characters in the title of the document would tell you the they were not allowed.
As of 10.7.1, saving with, for example, a : in the filename will automatically convert it into a permissible -.
[crarko adds: I tried this with TextEdit in 10.7.2, and it did work as described. The hint author indicated it also works with Office 2011, so I'm assuming this will happen in all standard Save dialogs.]
The normal way of associating a picture with an e-mail is using the Address Book. While this makes sense for the humans I'm interacting with, I don't want to add an address book entry for firstname.lastname@example.org. You can get around this by using an old NeXTSTEP era mechanism that still works in Lion.
Just add a tiff file with a name e-mail.tiff into the folder ~/Library/Images/People, restart Mail.app and you are done.
So for Flattr e-mails, you would have the logo at ~/Library/Images/Peopleemail@example.com.
There are more details contained in this blog post.
[crarko adds: I haven't tested this one, but it should work with most, if not all, versions of Mail.]
You can customize 'All My Files' so a new Finder window will display whatever search you prefer.
All My Files is great for opening a Finder window and easily seeing recent documents. I found list view more useful with lots of PDFs and other docs with long and similar names. But list view will show an endless list going back as far as your oldest files. I wanted something else, in this case, only a list of files opened in the last month.
I created a new search and then made that 'All My Files.' After creating and saving the search:
[crarko adds: I admit I'm not sure how this is any better than just creating a new Smart Folder with the appropriate search criteria. But if you so want to modify All My Files instead here is a way to do it.]
If you plug in your iPad/iPhone/iPod then iPhoto or some proprietary image transfer application automatically opens even if you don't want it to, because the device is regarded as a camera.
You can change this behavior by using Apple's Image Capture utility to set defaults for each device.
This problem has been plaguing me for a while. I have a Nikon DSLR, a Canon Point and Shoot, an iPad, an iPod touch, and now an iPhone. All of them are treated as cameras when I connect them via USB.
I frequently use Nikon Transfer to move images from the Nikon DSLR, and it always opened no matter which of these devices I connected. The preferences in Nikon Transfer don't help, and the options in each of my iDevices preferences gave me nothing to manage this either.
So, when I was digging through Image Capture (it's in /Applications) to decide how to handle my new iPhone's images, I found a device list on the left, and options to change what app would open when you attached them. Once can even determine where to move/copy files on the hard drive. I set my iDevices to open no app when connected and now the only thing that opens Nikon Transfer is my DSLR.
[crarko adds: Image Capture is one of those very useful and often overlooked utilities. It's worth getting to know better.]
This hint shows a way to close an application AND its windows.
In Lion Command+Option+Q lets you quit an application and close all of its windows so that when you reopen the app there won't be open windows.
[crarko adds: In Snow Leopard it there are options to close all windows (generally Command+Shift+Option+W) but it's not tied into the Quit operation. I imagine since Lion re-opens all the previous windows when the application launches the new shortcut was added to prevent that.]
This keeps the fullscreen display of Flash videos open on all spaces. Nice for watching streams/videos on a second display (TV) and then switching around.
You'll need a plist-editor like XCode (or just a text editor if you're comfortable with that) and Flash version 10.2 or later, so it remains open when the application focus changes.
First backup and then open the file ~/Library/Preferences/com.apple.dock.plist with your editor.
Add a new line under workspaces-app-bindings
Name it org.mozilla.plugincontainer.
Change the data type to Number.
Set the value to 65544.
Save the file.
Log out and back in.
Works on 10.6. but I cannot check this on Lion, so please do and comment.
[crarko adds: I haven't tested this one. I admit I'm not quite exactly sure what this does, so exercise some prudence. Make sure you do the backup before making changes to the plist file. If you are adventurous and give it a go, do post results in the comments.]
When you use Mail, or another email client, together with a Gmail account you will surely know that clicking on a message and pressing the delete key does remove that message from Inbox folder but leaves a copy of it in the 'All Mail' folder on the Gmail server. Effectively the message has not been deleted. This is the default Gmail behavior.
While I like using Mail.app with Gmail I don't like the 'All Mail' folder. Here's how to configure Mail so a deleted message ends up in the Trash folder on the Gmail server.
In Mail.app, under Preferences click the Accounts icon. Select your Gmail account. In the Trash section check the box 'Move deleted messages to the Trash mailbox' and check the box 'Store deleted messages on the server'. Close the Mail.app Preferences.
On the left side where the Mailboxes are located, expand the Gmail folder, and click on the Trash folder. Next, from the Mail.app menu select Mailbox » Use this Mailbox For » Trash.
Now messages you delete in Mail.app will from now on be moved to the Trash folder where you can permanently delete them by selecting them and pressing the Delete button on your keyboard or by enabling the automatically delete after x number days setting in Mail.app preferences.
I hope you find this hint useful. It's tested on Mac OS 10.7.2 Mail 5.1.
[crarko adds: It looks to me that these options are available in 10.6.8 Mail as well, although I haven't verified that it works the same.]
You can manipulate Collada (.dae) 3D objects in Lion.
I was converting a Sketchup 3D file to Collada to be able to open it in Cinema 4D when I noticed the Finder icon generated was looking same as the model. I could Quick Look at the file and discovered that you can manipulate the whole 3D right into Quick Look, or Preview.
[crarko adds: I haven't tested this one. The file type is one that is used for a lot of interchangeable 3-D graphics modeling in various game engines.
According to several comments, this also works in Snow Leopard.]