This is another type of application that you may not be familiar with. Growl is a program that shows notifications, little messages pop up on your screen. The great thing is that programs can let you know some task is completed, new mail has arrived, hardware was added to your system etc etc. This all happens without interfering with what you were doing. The messages do not distract, are yet informative and above all: different programs let you know stuff in a consistent way.
Many programs have Growl support built in; for some you can install little helper scripts or programs. I have installed GrowlMail and HardwareGrowler.
The program is free and super useful, so go get it!