D. Tomato wrote:

Our Krups vegetable/rice steamer is due for replacement. But my wife
doesn't want another plastic steamer because she's afraid they might
have harmful chemicals.

I realize this may border on off-topic, but upon what evidence does she base
such fears? Hard plastics, such as those used for steamers and other
"heat-proof" uses, are chemically stable. It's the soft ones like cling wraps
(estrogens, etc.) that might have some valid concerns.

...
Are there any good steamers out there that aren't plastic or aluminum?
I know there's bamboo, but I want a machine that's reliable and easy
to use (throw in the food and set the timer).

Unless you opt for bamboo, I think your only other choice will be stainless
steel. You have two choices and both are inserts for pots. First is the standard
collapsible basket that only costs a few bucks. Second is a steamer insert,
which can also be used for pasta if your pot and the steamer fit together right.
The following link has a variety of those.

http://www.cooking.com/products/shpr...0&ClassNo=0121

The only "standalone" SS steamers I'm familiar with are very large and for
restaurant use. Those are way too big for the typical home kitchen, much less
for the countertop. They also run in excess of $1500 new (for the smaller ones).