Just upgraded to 5.0. When I double-click a source file in project view, IDEA 5.0 crashes on OS-X 10.4.2. Calling up the same file via CTL-E (least recently used) works fine. Build 3431 does not work, either.
Crash log indicates, that it has something to do with fonts:
0x9deaf000 - 0x9e0c2fff libawt.jnilib /System/Library/Frameworks/JavaVM.framework/Versions/1.5.0/Libraries/libawt.jnilib
0x9e13d000 - 0x9e18cfff libfontmanager.jnilib /System/Library/Frameworks/JavaVM.framework/Versions/1.5.0/Libraries/libfontmanager.jnilib
0x9e212000 - 0x9e21ffff liblaf.jnilib /System/Library/Frameworks/JavaVM.framework/Versions/1.5.0/Libraries/liblaf.jnilib