If you are starting with Linux and you would like to give it a go then VirtualBox is the best option:

Pros:

• No modifications to your system;


• No harm done if something goes wrong and you mess up Ubuntu completely;


• Ability to create snapshots and restore them on the fly, ie: Create a snapshot before issuing a weird command that you are not sure about, if something goes wrong you can restore the snapshot and continue with your life;


• Mappings can be done so that the file from your Windows system are shared with Ubuntu without the worry of mounting file systems, its easy pie;


• If you find that you do not like Ubuntu and you want to remove it from your system you can simply remove VirtualBox and delete the virtual machine files and your system will be back to were it was, no harm done.


• No partitioning mistakes! The disk Ubuntu is going to install to is just a file inside your Windows system, delete the file, Ubuntu is out and you can start over.
  
  
  
  • Create as much partitions as you like;
  
  
  • Play with mount points as you desire;
  
  
  • When in doubt go back and re-do it as you like
  
  
  • No harm done to your Windows installation
  
  

Cons:

• Not as a fast as a live installation, still bearable and great to try and use;


• Eye candy supplied from accelerated graphics is not present or is not as fast as it could be, depending on the system. It will still look imba, but not the same.

The 2 points that would make it a bad choice to install it in a virtual computer do not overcome the pro points, just the simplicity of it should be the main reason to use Ubuntu in VirtualBox if you are using it for the first time.

Later, when you are confident that you want to use it and you are ready to do a real installation you will have all the steps covered and you will feel confident on what to do.

Other best options are:

Wubi

• Ubuntu is installed in a file in a Windows directory (normally c:ubuntu
oot), GRUB will replace your Windows boot manager and will let you choose between booting Windows or the Ubuntu system inside that file;


• Its a good option because you are actually booting to Ubuntu directly


• It makes partitioning easy since everything is done to the file keeping Ubuntu, not really modifies your hard disk partitions


• Its bad because if GRUB for any reason gets messed up you will need to go trough some work to restore it, not hard, but for a newbie nothing is simple.

Windows partition resize

• Resize your Windows partition using the Ubuntu LiveCD or the Ubuntu installer and install Ubuntu in to its rightful place!


• It allows your to keep Windows and Ubuntu on the same computer, allows you to fully play with partitioning and choose mounting points directly in your hard disk space


• Installs GRUB to manage the dual boot between Ubuntu and Windows;


• Its bad because it installs GRUB and for the same reasons as a Wubi install, if GRUB gets broken you need to fix it. Also resizing can be dangerous (normally is not), make a backup before you do it. Careful so you don't accidentally overwrite any Windows data!


• Can be a problem if you somehow destroy Ubuntu or mess up your Windows system from Ubuntu and then you can't boot anymore.

Other options

LiveCD booting

Just download and burn the Ubuntu CD from the downloads site, boot from it and use it as a LiveCD. It will be slow because it is using the CD as the system but it wont harm your system or require installation. Once you reboot everything that was not saved in to your Windows disk or a removable media will be lost.

Install to a USB drive

Most systems now a days allow you to boot from a USB drive. You can install Ubuntu to a USB drive and use it as a spare. GRUB will be installed to the USB drive, it will be a real system and act like one.

Good thing about this is that you do not modify your Windows install.

Bad thing is you need to select the USB drive each time your need to boot in to Ubuntu, or you need to modify GRUB to recognize Windows and give you the option to boot to it.

This is a good option if you have a spare USB drive around and your system allows you to boot from USB.

For a newbie it is always better to have it installed in a way that what ever happens your previous system is safe and that no big changes are done. For the moment stick with a VirtualBox install and when you are more confident move on to the next step. Better a slow start that a fast and disastrous one.