Canonical releases just a few days ago Ubuntu 12.04, which according to their roadmap  will be supported until 2017. If you have been following this blog or even tried out Ubuntu on your 4720s you know that the ride   has not always been smooth, so it is time for another post.
This release does a really good job on the 4720s regarding power consumption. With all tricks pulled, 11.10 wouldn’t consume less that 15W reaching about 2:30 . Now, with an empty desktop with WLAN enabled it consumes 12W reaching more than 5 hours.
And the rest
Skype isn’t in the default repositories, so one has to download it from the manufacturer. Even so it is again unstable.
Custom keyboard shortcuts don’t work reliably 
Resources and references
 gnome-shell most keyboard shortcuts not working
 Ubuntu 12.10 on the HP Probook 4720s
2 thoughts on “Ubuntu 12.04 LTS on the HP ProBook 4720s”
I have the same notebook as yours, and I was unable to use an external monitor with 12.04 with the proprietary ATI video driver. Have you tried that yet? I reinstalled Mint 9 (based on 10.04) since I needed both my right-click and an external monitor. I was impressed overall with 12.04 and really wanted to keep it, and I'm hoping either this is resolved with Mint 13 or updates fix this.
Sorry, no, I didn't try it but now that you mentioned it I'll have a look.