So many changes, mostly for the better, starting with Fields of Valor. Let me know if you can't find reference material on that. It will make your lower-stage leveling SO much easier, safer, more fun.
As to LSs: I'll give you four linkshells to consider that I have pearls in and like very much, but you should also read the stickied thread atop this forum for even more to consider. Get the best fit you can! Your linkshell is your family.
Axiom is a medium-sized shell of long standing with a mix of new, intermediate and older players. http://www.axiom-online.org/
has more information. I am a sackholder there. And by coincidence, Axiom happens to have several recently-returned, or simply brand new, players, so you would have some folks who have that in common with you.
Musketeers is a larger shell weighted towards the veteran side, but friendly, well-organized and still casual, although they do their share of endgame events along with lower-level things. http://ffxi-musketeers.com/
Triumvirate spun off from Axiom about 2.5 years ago. Still has a nice mix of levels, and everyone is friendly. http://www.triumvirate-forum.com/
(See the taru bard on their front page? That's me!)
Moghat is a spinoff of sorts from Triumvirate, smaller but very tight-knit; everyone is super friendly. http://moghat.com/
You can shop around a bit, but generally it's best to have just one main social shell. (Heck, I wish all my friends were in just one shell ...)