Is there a good, lower cost alternative to the Canon flashes?

The title says it all.

Would you consider the 220EX?

Depends on your definition of "good".

There are several aftermarket brands that work fine as E-TTL flashes. They don't have all the bells & whistles of the higher end Canon units and perhaps don't have the same "feel" in terms of construction, but some of them are a very good value.

The most popular among these is the Sigma EF-500 DG Super. Sigma also makes an economy unit, the EF-500 DG ST, with the same build and power but lacking high speed sync and some other features. I have two of the Super units and I'm happy with them considering the price I paid. If you go to this web page and scroll down to flash units, you can compare the Sigma Super with the various Canon Speedlites.

Promaster, Sunpak and others also make some nice E-TTL flash units. Make sure you study their features and specs carefully.

The 220EX unit that Suzy mentioned is only marginally more powerful than the built-in flash on today's cameras and has no bounce or swivel capability. I wouldn't recommend it. For a few dollars more you could get the Sigma ST unit with over 2 stops more power and a bounce/swivel head.

Thanks, Curtis. I'll check into the Sigma. Great web site you recommended by the way!