Although from the sound of things, they said that they planned on using a lot of what was implemented in FFXI, so that might be in there...
Item: Evoker's Horn.
Sure, there's better pieces of gear for any SMN, but the FF staple for Summoners is the Horn. Even if there is no SMN class, I'd hang it up in my Mog House, or W/E.
Finally, Frosty Chocolat, my Chocobo.
He ran away, came back, played, went to camp, I watched him hatch and grow into a great mount.
FFXI: Odin - Merylstryfe Summoner Woo Hoo!