Yeah thinking about it, X did have a fantastic battle system, i especially liked it how you could change your characters in battle, great idea. I quite liked the sphere grid too, complicated but a clever way to progress levels. The only criticism was that you didn't get many summons, well not as many as other FF's.

7 also had a great battle system, pretty simple but enjoyable. I like battle systems where you do not have to rely on only attacks or magic or summons. In 7 all were seen as just important whereas for example FF8 you relied too much on summons in my opinion.