But once a person has bought all the expensive new electronic toys, electricity seems such a minor part of the total that the first thought is to just not buy another electronic toy (and use the others a little longer) rather than cut back on electricity use.

What do you base this opinion on?

Getting a person's house sealed tighter, or adding insulation requires some thought and an additional expenditure, so people tend to put it off.

With cheap electricity, perhaps. If cap and trade (or a carbon tax) is instituted, then that provides a greater incentive to start taking measures, many of which cost little to nothing.

Changing light bulbs could help too, but the light bulbs look more expensive.

It's well known that CFLs are much less expensive overall, so it's hard to understand where you are getting your opinion from.

But once a person has bought all the expensive new electronic toys, electricity seems such a minor part of the total that the first thought is to just not buy another electronic toy (and use the others a little longer) rather than cut back on electricity use.

That may be what your intuition says, but it doesn't seem to be true.

Take a look at per-state electricity data. Take a look at the residential price/consumption figures - there seems to be a strong correlation between higher prices and lower consumption, both within regions (the North Central regions in the table show this very clearly) and between regions (compare North Centrals to New England or Mid Atlantic).

Available data seems to suggest that residential customers in the US are actually fairly sensitive to electricity prices, and that higher prices (due to shortages and/or carbon taxes) are likely to result in significantly lower consumption.