|How big it takes space in your harddisk depends on how much tools, apps, candies, etc you want. For minimalistics (basic GUI and apps), it shouldnt take more than 1 GB space (exclusive /swap). For normal users between 2-3 GB. The swap partition is about 1,5 - 2 times of your RAM.|
Linux needs at least 2 partitions. The root partition (/) and swap partition (/swap). The /swap is the same as virtual memory in Windows. The root partition (/) is where you install the system. There are some filesystem types to be chosen: RaiserFS (the default for SUSE), ext3 (the default for RedHat, Fedora, Debian), XFS, JFS, Raiser4 (more advanced RaiserFS but still has some problems), etc. My favorite is XFS.
Many users use 3 partitions for their Linux systems: /, /swap and /home. /home partition is where you store user specific files. If you dont specify the /home partition than it will be saved in / (root partition). The separated /home makes sense in case you need reinstall Linux, your private files wont be got formatted (as long as you take extra care during installation process)