A500: My MegaAChip 2MB Agnus board. I was into music, and heavily used OctaMED 4. I went from 512k Chip (usable for samples) and 512k fast to 2MB all Chip (all for samples!!!) That was also when I installed Kickstart 2.04
A1200: Jetfire (?) 030/40 It was a cheapie accelerator, but it let me introduce myself to the Internet, because Miami would not let me use any internet apps at the same time on a stock 2MB A1200 lol On that note I guess I should mention the SupraExpress 56e modem from Diamond. Miami even had drivers for it! Unfortunately due to limitations in AGA bandwidth I had to run the serial port at 38400 baud and browse in a maximum of 128 colors lol