A dual drive system offers less opportunity for clever schemes but the following should provide a simple starting point.
Partition sda sdb ---- ---- 1 boot lib 2 swap news 3 /tmp swap 4 /usr /var/tmp 5 /var /home 6 / (root)
If you use a dual OS system you have to keep in mind that many other systems must boot from the first partition on the first drive. A simple DOS / Linux system could look like this:
Partition sda sdb ---- ---- 1 DOS lib 2 boot news 3 swap swap 4 /tmp /var/tmp 5 /usr /home 6 /var DOSTEMP 7 / (root)
Also remember that DOS and Windows prefer there to be just a single primary partition which has to be the first one where it boots from. As Linux can happily exist in logical partitions this is not a big problem.