As far as VI is concerned, I'd recommend either SNES ROM; fan-translated or American. The American version has graphics and dialogue censored whereas the fan-translation has a lot of unnecessary swearing that I frankly don't think belongs in there. It's your choice. With that said, I might suggest you look into some of the bug fix patches too, as the SNES version is one of the buggiest in the series.

The two DS remakes (III and IV) are only really worth checking out if you liked the originals and wanted to see them another way or what-have-you.