realkman666: He doesn't need arguments. Did you ever find out if copying files around with using Steam is respecting the terms of service.
Without being a lawyer, I'd say it depends on local jurisdiction. Quoting section 2G of SSA
Except as otherwise permitted under this Agreement (including any Subscription Terms or Rules of Use), or under applicable law notwithstanding these restrictions, you may not, in whole or in part, copy, photocopy, reproduce, publish, distribute, translate, reverse engineer, derive source code from, modify, disassemble, decompile, create derivative works based on, or remove any proprietary notices or labels from the Software or any software accessed via Steam without the prior consent, in writing, of Valve.
Emphasis mine. If local law allows you to make backups of your files, then you can safely copy them.
Section 2A also says:
To make use of the Software, you must have a Steam Account and you may be required to be running the Steam client and maintaining a connection to the Internet.
A steam account is a requirement, and the Steam client and/or an internet connection may also be requirements, but they may not be. So depending on local laws, and what lawyer you can get, copying the files to another computer doesn't seem to be breaking the SSA.
P.S.
Steam Community Moderators also encourage copying files to another computer, though as always, take a moderator's advice with a grain of salt.