80 GB is very easy to fill with software that will work on Amiga 1200 with 68030 accelerator and soon you will be searching for more space. Better buy CD burner for use with that machine also for backup purposes.
First thing to install is proper Workbench with good mod players. You can add some MP3 player too. Next install utilities and software - LHA, LZX, Directory Opus, Personal Paint and similar stuff. 500 MB will go here (0.5 GB).
Next look for Amiga games - direct HD installs - Simon The Sorcerer, Civilization, Colonization, Hired Guns, etc. Then WHDLoad games.
Then Amiga ports of PC games. Doom works fine and you can download the extra WADs with Star Wars, Star Trek, Batman. They work fine with ADoom on 68030 and you will occupy sever hundred megabytes with Doom WADs.
After you are done with the Amiga stuff you can continue with emulators.
AmiMasterGear works fine on 68030. It supports archived ROMS, so you don't need to decompress them. After AmiMasterGear, install ZXAM, Speculator and then Sinclair Software. I used to have two CDs with Sinclair Software working on Amiga - more than 1 GB. After you have installed the Sinclair, you can continue with MSX, NES, Apple II, ColecoVision, Dragon, Amstrad, Apple Mac, IBM PC and other bunch of emulators. You will fill that 80 GB pretty easy with native Amiga and retro computers software and soon you will need more space.