pdh, just wire the lights initially so that when every light switch is down, the lights are off. You may end up with some up and down during normal use, but during a power failure, put them all down, and you'll know the lights will be off when power returns. And, honestly, this doesn't even sound like a problem so much as an aesthetic preference and pet peeve- for anything actually critical, you should be securing the breaker and not relying on light switches anyhow. The electrical costs for a single light are negligible in the scheme of things, especially considering the low-likelihood of the kind of thing you're talking about. I mean, you're talking about 10 cents a day for a 60W bulb left on 24/7. About $1/month for a typical CFL. I have a bunch I just leave on 24/7 intentionally because.
3-way switches are indispensible, especially for rooms with multiple entrances. I have 4 light switches controlling my dining room chandalier, and wouldn't have it any other way. One of which is a push-button, boo-yah!
