Personally, a compiler/linker, code editor and form designer (and with a form designer probably some form of VCL would be required) would be enough for me. I never really cared about databases, web components or fancy component stuff.
As for Delphi for Mac OS X and Linux, as far as I know there isn't going to be a cross-platform Delphi IDE, just a cross-compiler from Delphi for Windows. Or did I miss some big news?

While I agree, Lazarus on Mac OS X is not as confortable to use as on Windows, it is definitely ready for developing all kinds of projects with. (I did some some freelance GUI work with it, a few programs for university and a lot of open-source/freeware applications.)
I guess if the Lazarus team develops their own debugger instead of using GDB this would.
Btw: For cross-platform development I would recommend to grab a November build of Lazarus where build macros are activated by default. So you can have one .lpi for one project instead having one .lpi for each platform you want to support. (Especially if you consider how much custom linker stuff you have to add when developing with SDL on Mac OS X.)