Well, Mr Bradshaw, unless you run your Linux box as "root" you would have little to fear from a worm even IF it was written to work in Linux. Mozilla mail has the "do not allow scripts in Email" set as a default, so a user would have to set that option *on* first...
Theoretically, it IS possible to write a Linux virus, but the users would have to run it with administrative privs to allow it to do any real damage to a system.... even then, watchdog programs like "Tripwire" would notify the system administrator of any changes to critical system files immediately.
I like Windows- it keeps me employed and very busy... if it weren't for all the bugs, patches, problems, and Virus chasing, I'd probably have been downsized years ago.
BTW- out "Caught virus count" at work (for "MyDoom" ONLY) is now up to 1,375