I would suggest playing FFIX since you've been playing the new school FFs, and I think FFIX could be a good way to get you acquainted with the old-school style, especially if you prefer 3D graphics to 2D and getting used to 2D isn't easy for you. I can't really suggest the PSX remakes of the SNES FFs (4-6) since their loading times are just horrible. If you want to play those FFs, you may way want to try their SNES or GBA versions. FFIV Advance was a great remake of the game, IMHO, and I've heard the GBA versions of FFV and FFVI will also be released quite soon.