Our systems typically come with:

• / on 8-12+ GB,
• /rescue on 220 MB,
• swap on 1GB - 2GB, (based on RAM size)
• opt: /win 8-12 GB (min), or up to half the disk (your choice),
• opt: /data 2+ GB for data interchange with the windows OS
• /home on the rest.

Experience has shown these to good sizes and a good partition layout. The root partition is big enough to let you add lots of extra software. Having /home on a separate partition gives you the freedom to format / if you want to install a fresh distribution of Linux in the future, without having to worry about your personal stuff. Separate /tmp and /var are not really needed on a portable system.

If you have us leave the windows OS on your system, we'll happily resize it to any size you choose, and put Linux on the rest of the disk. Many customers get something in the 5-10 GB range. Also, as most windows installations come on NTFS formatted partitions, your Linux kernel will not be able to write to /win (but you can read it). The optional /data partition is formatted as FAT32, so both OS's can read and write it.