Offence and Brainstorm released a very nice 4 KB intro at Solskogen this year. Not only does it contain nice effects, but it has great music as well. 🙂
The intro runs on an unexpanded Amiga 500, so no need for a faster CPU or more RAM.
Code and idea by Nosferatu
Music by Serpent
Design help by Pal
The intro can be downloaded from here: Hymn to Hipparchus download