I was just wondering, before I make a purchase, would it be better to get an 80gb or 160gb ps3 for FFXIV? How much space should I prepare for the game and future updates?
Even after years of updates to the game, there's no way that FFXIV will take up a full 80GB HDD, so that would serve you fine if all you're planning on is FFXIV.
If you plan on doing more with your PS3, then you might want to consider upgrading the HDD. There's a lot of games that have mandatory installs (up to ~5 GBs), Game saves, Download games/demos, and any movies/music/photos you want tot store can take up a lot of room.
Any 2.5 inch SATA laptop HDD will work fine, and it's a very easy upgrade to do.