When using an Amiga:
I miss a simpler external world (www, file formats, etc). It seems to me that many things have been made more complicated and proprietary but not always better. I do miss CD writing apps like Toast. Until recently, I missed USB (I have not installed Deneb yet.)
I don't miss registry files, desktop files, swap files, virtual memory, vast hidden parts of an OS, spyware, user log-in, tragic hippness (Macintosh).
When using any other machine:
I miss the Amiga philosophy, ie: simplicity, multiple ways to accomplish things, an OS so logically organized it seems transparent to me. I miss Amiga directory utilities. I miss near realtime responsiveness. I miss the ram disk. I miss the machine's dedication to me alone. I miss anonymity (increasingly more precious all the time). I miss the belief that only I am running the show.
When using XP:
I miss not being a target on the net. I miss being the only one in control. I miss the OS needing my permission to commit something the hard drive or other media.
When using a Mac:
I miss the OS treating me like an intelligent being. I miss flexibility, obvious and consistant functionality.
When using Ubuntu (on PS3):
I miss understanding. I miss simplicity. I miss product maturity. I miss a decent flash player and other codecs.
With my Amiga getting older, I will have to rely upon many different machines.
I seem to be a sucker for threads like this one, grin.