When I got my Macbook, I followed Albert Tross's tips. Very useful. I'll paste it here and hope it helps you:
Good luck!!!
1. Look at the serial number on the box ( see below )
2. Once the box has been opened in front of you check to see you have
the following items.. (Apple iMac)
iMac computer
Apple Keyboard
Apple Remote
Mighty Mouse
Cleaning cloth
Power cord
Install/restore DVDs
The Printed and electronic documentation
3. Look the computer over for scratches and marks especially the screen
4. Ask the shop assistant to boot up the computer and take you through
the stages required to setup your initial username, password and create
the Home folder. after this process you will be able to fully use the
computer NOTE ..If the Setup Assistant doesnt launch when its turned
on in the shop, this suggests its been switched on previously, which
might set alarm bells ringing (for example, it might have already been
registered with Apple, which could affect your warranty).
5. Once up and running look at the screen for the possibility of Dead
pixels , Note Dead pixels are always black - Stuck pixels are stuck in
one colour go to the System Preferences and to the Desktop/Screen Saver
settings. Select Screen Saver, click on Computer name, then click on
test. This will give you an almost all black background. Take a close
look around for any colored pixels that should be black. If you dont see
any then you are good to go
6. Bring up a Solid colored desktop or black wallpaper now look at the
screen for a possible problem like this .. Left side of the screen is
bright white, while its yellow in the middle and dull on the right. and
see theres no light at the bottom of the screen creeping onto the
image ( backlight bleed problem evident when the screen is black)
7. Put the computer under some load by Opening every application in the
dock at once, make sure at least ten open also open up lots of files
and applications and make it work. try to push the machine to get it
warm.
8. Play a DVD / CD
9. Play the movie trailers in Front Row and the Arabesque screen saver.
( Two screen freezing
classics )
10. Play with the Mouse and keyboard
11. Try out the remote control
12. When the iMac has been running for a few minuets , listen for any
odd sounds , Noises or
vibrations coming from the inside
13. Try out the iSight camera
14. Check that it goes to sleep and wakes up no problem,
15. Boot the machine several times
16 .Make sure that the back of the computer is not getting too hot
17. Click on the Apple logo in the top left and choose About this Mac.
It will tell you if you have
Tiger or Leopard Etc
18. Go into System Profile check the shown serial number matches one on
packing box
19. Buy Apple Care Protection Plan
20. Get a sales receipt showing the date of purchase, the machine
serial number and
the shop address
....The list may seem a bit over the top, but as I live a long way from an
Apple Store , I would feel better if I could check a few things first
before the long trip home."
Good luck!!!