They will all work. I have never seen a flat panel TV that did not include either a coax connection or an composite video connection that would support a VCR. However, you will likely not be thrilled with the video quality of VHS when watched on an HDTV. I do play a lot of kids videos for my 2 year old. He doesn't seem to mind the low resolution!
Enjoy,
TIC
Enjoy,
TIC