OS X Isn't for Developers 15 years ago
Eclipse.
That's enough to turn any iMac (well, any computers) into a programmer's powerhouse.
Last year, I led a small team of 3 devs to build a homebrew app for the NDS portable game console. We all used different OSes/IDE for development out of necessity (WinXp, Linux/Eclipse, MacOS X/xCode). Although I had no problem installing arm-gcc on the Mac and configure xCode to use the NDS-specific toolchain, I still prefer Eclipse.
Maybe xCode 4 will change that perception... Looking forward to give it a spin...
Yves McDonald