Read the Licence
From:
http://images.apple.com/legal/sla/docs/iwork.pdf
"2. Permitted License Uses and Restrictions.
A. iWork Single User License. This License allows you to install and use one copy of the Apple Software (whether trial or full version) on a
single Apple-labeled computer at a time. This License does not allow the Apple Software to exist on more than one computer at a time, and you
may not make the Apple Software available over a network where it could be used by multiple computers at the same time. You may make one
copy of the Apple Software in machine-readable form for backup purposes only; provided that the backup copy must include all copyright or
other proprietary notices contained on the original."
Now, I am not a lawyer, but neither is a software licence a binding contract. (the legality of a software licence is a totally separate discussion)
I read the above quote as "you can only use the single user licence on one computer at a time"
Highlights of my thinking
install and use one copy - AND USE being keywords here (ie install anywhere you want, but only run one copy at a time)
This License does not allow the Apple Software to exist on more than one computer at a time - EXIST being keywords here (ie loaded into memory and running). Until a piece of software is loaded into memory, it is just 0s, 1s, and Metadata. It only exists when it is running.
Since you are a single user I believe it is fair to allow you to use your software anywhere you want, so long as it is only YOU running it. YOU are not a family, and should not have to buy a family pack.
If you wish to challenge my thoughts based on legality, fine. However then you open up the whole "is a EULA legally binding" issue.