Just bought a Samsung Series 9 laptop (I7, 128GB SSD) with Windows 8 preinstalled. Can I remove and save Windows 8 (perhaps for future use) and install Ubuntu instead?
Yes, you can. Chances are the laptop has UEFI or Secure Boot which complicates things. Also the laptop probably has a recovery partition. Keep it! Normally you should be able to reinstall Windows 8 using the recovery disk if you decide you need it. I'm pretty sure the Windows 8 partition can be removed, but not the recovery partition!
There is more information about UEFI/Secure Boot at the Ubuntu Documentation UEFI wiki.