I'm not sure it is a waste of you plan to upgrade to HD in the future, but I'm not sure it is the best thing you could purchase.
Yes, the DVD would hook up via component video. If you got a HD cable box, then you would need some sort of component switcher since there is only one component connection on the display.
You may want to consider a display like the Samsung 4232 which has internal tuners that allow for OTA HD reception and if you go HD, it has an internal CableCard slot which allows you to avoid paying for an external cable box.
Please though, if you are going to reference equipment, list the brand, make model, etc. so that you can get solid recommendations for that product.