I've installed R3.0 on my Mountain Lion Mac and after some trial and error the version of GTK suggested by http://r.research.att.com/ for R3.0: GTK+ 2.24.17 framework.
I load the package into R3.0 and run one of the demo. I see (for an instant) that a graph is generated, but immediately R crashes. Typically the crash takes place when I run the line "win$showAll()" (CairoDevice work no problem). This is the beginning of the error log generated (with the details of my configuration). Thanks!
Process: R [2307]
Path: /Applications/R.app/Contents/MacOS/R
Identifier: org.R-project.R
Version: R 3.0.0 GUI 1.60 Snow Leopard build (6476)
Code Type: X86-64 (Native)
Parent Process: launchd [231]
User ID: 501
Date/Time: 2013-04-07 23:54:11.976 +0100
OS Version: Mac OS X 10.8.3 (12D78)
Report Version: 10
Interval Since Last Report: 11186 sec
Per-App Interval Since Last Report: 1133 sec
Per-App Crashes Since Last Report: 11
Anonymous UUID: 2C9EB7F4-E0B7-FDC4-7300-075C23CD86BB
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Application Specific Information:
Assertion failed: (_cairo_status_is_error (status)), function _cairo_error, file cairo-error.c, line 68.
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libsystem_kernel.dylib 0x00007fff8afbd212 __pthread_kill + 10
1 libsystem_c.dylib 0x00007fff867ccb54 pthread_kill + 90
2 libsystem_c.dylib 0x00007fff86810dce abort + 143
3 libsystem_c.dylib 0x00007fff86811e2a __assert_rtn + 146
4 libcairo.2.dylib 0x000000010d383cdc _cairo_error + 48
5 libcairo.2.dylib 0x000000010d37c6f7 _cairo_set_error + 19
6 libgtk-x11-2.0.0.dylib 0x000000010eca326a gtk_default_draw_focus + 554
7 libgtk-x11-2.0.0.dylib 0x000000010ec63dfc gtk_range_expose + 1644
8 libgtk-x11-2.0.0.dylib 0x000000010ec7e2b8 gtk_scale_expose + 120
9 libgtk-x11-2.0.0.dylib 0x000000010ec22e79 _gtk_marshal_BOOLEAN__BOXED + 169
10 libgobject-2.0.0.dylib 0x0000000109642455 g_closure_invoke + 245
11 libgobject-2.0.0.dylib 0x00000001096524c8 signal_emit_unlocked_R + 2216
12 libgobject-2.0.0.dylib 0x0000000109653528 g_signal_emit_valist + 3336
13 libgobject-2.0.0.dylib 0x0000000109653a64 g_signal_emit + 116
14 libgtk-x11-2.0.0.dylib 0x000000010ed38bd8 gtk_widget_event_internal + 664
15 libgtk-x11-2.0.0.dylib 0x000000010eba0fc1 gtk_container_propagate_expose + 369
16 libgtk-x11-2.0.0.dylib 0x000000010eb72e06 gtk_box_forall + 54
17 libgtk-x11-2.0.0.dylib 0x000000010eba3936 gtk_container_expose + 150
18 libgtk-x11-2.0.0.dylib 0x000000010ec22e79 _gtk_marshal_BOOLEAN__BOXED + 169
19 libgobject-2.0.0.dylib 0x0000000109642455 g_closure_invoke + 245
20 libgobject-2.0.0.dylib 0x00000001096524c8 signal_emit_unlocked_R + 2216
21 libgobject-2.0.0.dylib 0x0000000109653528 g_signal_emit_valist + 3336
22 libgobject-2.0.0.dylib 0x0000000109653a64 g_signal_emit + 116
23 libgtk-x11-2.0.0.dylib 0x000000010ed38bd8 gtk_widget_event_internal + 664
24 libgtk-x11-2.0.0.dylib 0x000000010eba0fc1 gtk_container_propagate_expose
I too had this problem. Here is how I worked around it using macports gtk2 -- not the http://r.research.att.com/ version. This was with R version 3.0.1 (2013-05-16) -- "Good Sport", also compiled from source.
sudo port install gtk2 ## (X11 -- not aqua)
export PATH=/opt/local/bin:/opt/local/sbin:$PATH
R CMD INSTALL RGtk2
R CMD INSTALL cairoDevice