What bike to buy to replace CitiBike?
Did you like the CitiBike?  If so look for a bike like that.  A commute bike will normally have slightly larger tires - 28mm-35mm.  If you want fenders then get a bike with fenders or at least will take fenders.  If you want a rack then get a bike with rack or at least will take a rack. Many manufacturers now have lines called City/Hybrid/Mulituse/Urban (or to that effect).  Kind of need to decide if you want flat bars or drop bars - you can get commuter type bikes both ways.  In NYC a single speed might be enough.  A lot depends on what you want.  Also how well can you lock it up?  If you have to leave it out then go cheap.

After I first answered you added that you like the CitiBike.  Look around.  Fender and basket are going to be pretty easy to find.  Internal hub is not going to be as easy.  A nice internal hub is more expensive but a lot of people like them. My neighbor got a cheap internal hub and has trouble with it.  If you go the internal hub route then get a nice bike.  Hopefully you will get some specific recommendations.