clever's got the right idea, with that much space and it just being a personal/learning/desktop machine, there's no need to breakup the partitions.
Just because I'm bored and can't seem to fall asleep, here's a bit of explanation of the more commonly broken off parts
/boot - some distros break this off for storing your kernel, kernel modules, and bootloader stuff. The theory being "the stuff you need to boot"
/var - this is probably the most important one to break off in servers. /var is where logs go, and if you're not paying close enough attention they might fill up the partition. if /var is its own partition, the only side affect will be you'll loose your log data till you find some more space. If /var is just a directory within the / partition, you'll crash the whole machine.
/usr - some people make this a seperate partition, and then make it a read-only mount. This can have a minor security benefit in that it will slow down a dumb hacker, or perhaps trip up a poorly written exploit (if neither of them realize they need to re-mount the drive read/write in order to install their various backdoors). This partition is also commonly broken off so that it can be NFS mounted or shared in some other way across multiple machines (again read-only). This is useful in clustering situations.
/home - since home is usualy where people's home directories wind up, it will grow the most depending on how many users are on the system. Again like var if you're not watching it close enough it could fill up and crash the sytem if it is within the / partition.
bart