Erm, I'd suggest that you make a /home partition of some GB size, for your documents, audio/video, and for compiling things (some people like to untar stuff into /usr, but that breaks when /usr is remote mounted or fundamentally unwritable.
Having /boot seperate is only needed if you are running more than one OS, and either need to synchronize your kernels or duck under BIOS limits.
A seperate /usr is a very good idea, thats where the action is!
A seperate /var helps you learn what caused cataclysmic failures if the / is fried, and also keeps runaway logs from choking /.
A seperate /tmp is sometimes useful, especially when your / is small and you want to keep it from being choked.
I tend to use bigger swaps, but that only because I tend to run servers.
Also, consider where you want your servers' data to be, if you intend to run servers. I like to keep all my servers' content files in subdirectories of /home, but thats somewhat nonstandard.
It's really your choice how you do it, of course, but I would probably do...
This comes out CLOSE to 18GB, I'm to tired for math.