Xcode is most likely to be able to handle everything best. I say this because you will find it difficult to impossible to effectively develop for iOS without using Xcode, even if you use tools like PhoneGap because at some point you'll almost certainly have to use Xcode anyway to get provisioning right. Essentially any tool can be made to work for webOS, and as for Android I think you'll find it possible to work in Xcode but it won't be as easy as if you worked in Eclipse.
In short, I'd say use the right tool for the right job, and don't worry about using multiple tools. In the end you'll probably be happier supporting multiple development environments than struggling to cram your work into a single tool.