I'm using an A1200 with 50Mhz 68030 and 16Mb RAM.
My daily computing needs are email, FTP, basic web broswing (I could probably survive with lynx/links), email and ssh/telnet. Perhaps this doesn't make me a typical modern day user - but on a daily basis I don't need to transcode video files or do anything hugely CPU intensive.
iBrowse seems to manage ok. I dont' spend all my day on facebook/youtube and I was amazed at just how responsive it was running webmail (Squirrelmail).
If gimp and openoffice [1] were ported to 68k AmigaOS I'd probably never need to switch on the PC again! Although, switching from Amiga to PC does make me appreciate how much we take high res displays for granted nowadays.
[1] I do realise both these apps would be near impossible on a 68k Amiga ... especially OpenOffice :s