>Linux users don't run all the time as root -- this is the greatest protection.

The smart ones don't! :)

Another good protection is, if it is possible, to leave the computer off when not in use. This is also more energy efficient, obviously. Long uptimes are so easy to obtain anymore the only effort required is the waste of electricity needed to let a box set there and run.

About 8 months ago I got a new Athlon 1GHz with 512MB of RAM and serveral powered peripherials. With the UPS and sound transformer on line the box was burning about $1.20/day or $36/mo in electricity. That wasn't counting my wife's box, which is also on 24/7 except for thunderstorms or vacations. But with her monitor and printer off her box only burns about 25 cents per day or $8/mo in electricity.