After much research, I finally purchased an Excalibur Dehydrator. Previously, I had a round dehydrator someone had kindly given me, but I just wasn't satisfied with it. The heat didn't distribute evenly, so the trays needed to be rotated frequently. And, it really didn't hold that much. This model is well worth the money. The temperature is adjustable and it has a timer, so it can dehydrate away, even if you're not home.
The Excalibur Dehydrators come in five and nine-tray options; I selected the five tray model simply because I have limited storage space. But, the main selling feature for me was that the trays can be removed, and it can be used for raising bread or making yogurt.
Update, Spring 2011
I am still extremely pleased with this dehydrator! I use it for dehydrating fruits and vegetables and making yogurt. My neighbor is getting into vegetable gardening and was researching dehydrators; she asked me what I thought of my Excalibur, and I told her I would highly recommend it!