I recently upgraded to Ubuntu 12.04 from 11.10. And after having some issues with the desktop, I installed the fglrx driver for my video card. The one that's distributed with the Additional Drivers app in Ubuntu. Here's what I have:
lspci | grep ATI

01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI RV710 [Mobility Radeon HD 4500/5100 Series]
01:00.1 Audio device: Advanced Micro Devices [AMD] nee ATI RV710/730 HDMI Audio [Radeon HD 4000 series]

fglrxinfo

display: :0 screen: 0
OpenGL vendor string: Advanced Micro Devices, Inc.
OpenGL renderer string: ATI Mobility Radeon HD 4500 Series
OpenGL version string: 3.3.11627 Compatibility Profile Context

From time to time when I'm shutting down the system hangs and I've got an error message regarding the fglrx driver (I've disabled the splash screen for the shutting down so that I could see what's going on). Unfortunately I can't copy the message as at the moment it's outputted I can't do anything, but just watching it At the end, the only way to shut down they system, is to use the power button. And off course the next time I power up my laptop, the system has to clean up the journal.
I'm thinking about using the official ATI Catalyst driver, version 12.6... as my video card is now considered legacy, according to ATI
Has anyone used it? Could you share your experience with it? I really hope that this could solve the shutdown problem I have...