Just as effective is to use NiMH rechargables and just charge them frequently. I have two blinkies, I just take them off the bike on my way in to work once a week and drop the batteries in the charger, then an hour later toss them back in the lights. Takes about 1 minute once a week. In my tests the batteries were actually good for at least a month before they start to get dim. By charging once a week I don't forget it, and the one set of batteries should be good for at least 4 or 5 years.

Now that they have NiMH cells with low self discharge (only lose about 30% in 6 months), I'm switching the last few things in my house over. The remotes and clocks will get them as the alkalines get used up, those were the only few things left with alkalines anymore. I just set a reminder to cycle them all through the charger about once every 6 months.