I make music and sounds for video games. Which software should I install on Ubuntu Studio for this purpose?
The Linux Multi Media Studio is a must for every audio producer.
If you are familiar to MS Based Audio Tools, like: Fruity Loops Studio, Sony Acid, etc. You can feel happy with LMMS.
Screenshots from the official website at: http://lmms.sourceforge.net/screenshots.php posted here for your convenience:
You can create, use, edit samples from audio files, such as wav, mp3, midi, etc.
For audio capturing, manipulation, editing, DSP, etc. I can suggest you the Audacity, which is more like a multi-track waveform sound editor.
Screenshots from the official website at http://audacity.sourceforge.net/about/screenshots placed here for your convenience:
Additionally you may wish to give a try to the Israel Remix Team Multimedia 11.04 found at: http://www.israelremixteam.com, which features lots of useful audio/video tools which will make these tasks easy.
A screenshot of my System using the Israel Remix Team Distro posted here for your convenience:
The left side monitor is showing the menu with Audacity and Ardour in the background, the right side monitor is showing LMMS with a new project.
Your question seems not to be answered with a single one but this may be useful for you.