The "zoom" function on a TV usually just effectively makes the pixels larger to fill the screen and degrades the image as a result.
The best DVD's for a Widescreen TV are those labeled "anamorphic" or "enhanced for 16:9 televisions" (available on virtually all recent releases). The image is squeezed horizontally on these discs to fit in a standard 4:3 window, so all of the horizontal and vertical information is preserved. When played back, your widescreen TV stretches them to fill the screen, undoing the squeeze and restoring the proper aspect ratio.
Letterbox discs lose vertical resolution, as they are "shrunk-down" to fit horizontally in a 4:3 window, and Full-Screen discs lose horizontal content, as they are cropped to fit in a 4:3 window.
I would just look for some reviews to help you find the best solution. For a long time, Oppo (http://www.oppodigital.com/
) was regarded by many as making the best upconverting DVD players, particularly for the price. As I said, I personally consider the Toshiba XDE-500 (http://www.bestbuy.com/site/olspage....egories&ks=960
) to be the best-performing upscaler I've seen and at less than $80 now, it's pretty cheap.
Unless the Component Converters you ordered are also upscalers, they aren't going to give you anything you don't already have. HMDI doesn't upscale, it simply transmits video and audio as a digital signal. Unless you spent some serious bucks, it's unlikely any outboard upscaler is going to be much better than the upscaler built into the TV and will likely be worse than the upscaling performed in an upconverting DVD player, where the player has access to data on the DVD that can improve the upscaling results.