I'm thinking about installing Ubuntu ( dual boot ) as I might like it but I'm not sure whether I should choose to install alongside Windows 8 or something else.
I do have 100 GB unallocated already for Ubuntu on my D:/ drive so I'm good to go.
I've seen people configure their partitions specially ( they created swap and then used the remaining unallocated to install Ubuntu ). Do I need to do this? Or will the installer handle it for me.
As far as I go, never trust automatic partitioning options in Ubuntu installers, as you may end up with nasty surprises. When installing Ubuntu, personally I always prepare the partitions manually. Since you want to keep a dual-boot set-up, most flexible would be to create a new extended partition and inside it create the several logical partitions.
In the extended partition I usually I reserve:
swap (or whatever appropriate given your RAM)/ which will contain all your system files (but some will say that this is overly generous, as 15-20GB could suffice given your installation habits)/home which will contain all your user dataI tend to use ext3 file system for the above partitions for reliability reasons (but you could of course use ext4 or reiserfs if you so prefer). Sometimes I include a /boot partition no bigger than 500MB using ext2, but I cannot remember if this is more hassle than necessary; from memory, this is where kernels and grub config files end up.
Additionally, see My approach for replacing current Ubuntu with newer for a discussion on how manual partitioning can be approached.
Do it alongside, this way if you don't like it you can turn back,
The installer will take a portion of the HDD as its own and format it to EXT (this is invisible to Windows 8) and a slight portion for linux-swap (which has its own format type) you can predetermine this on install.
To dual boot the installer should set it up for you with grub, but if not easyBCD, will do the same task from the Windows 8 side.
