I often feel like IOS apps work well despite Objective-C, not because of it. The idea of someday having to maintain a server written in Objective-C scares me.
I would second this, while I am sure there are many on here in which Objective-C fits the way they think, I personally would hate to have to use it for the server side of the equation. Apple and before that NeXT did a lot of work to make developing UI based system, with Objective-C easy. The efforts for anything on the other end of the pipe seem to be more developed out of necessity than inspiration. Cappuccino, which is external to Apple, and has created Objective-J (GWT for Objective-C) seems to have put more inspirational work into Objective-C for the server side, that being said, it's still not my thing, but I know others that have used it and love it.
iOS and Mac apps are a lot of fun to write and work with, for two reasons:
1) Objective-C is a pretty decent language. It's not perfect, it has some baggage, but overall it's pretty neat and has enough flexibility to build a good platform.
2) Apple has built two good platforms, in AppKit (Mac) and UIKit (iOS). These frameworks are the real secret sauce, not the language. They're comprehensive and generally well-built, and make working on Apple platforms a joy. They actually take advantage of the unique features of Obj-C.
If someone could produce a web framework of the same caliber as UIKit, I think Objective-C would make a great server-side language. But building such a framework is not easy.
