I still use my towerized A3000 fairly regularly. I prefer ImageFX when I need to do some photo editing/manipulation and I still use Bars&Pipes for making music. If I need to edit textfiles there's nothing like CED and YAM is till used for some of my personal email.
But there is nothing I can't do on other platforms. All of these programs run well on UAE and there are of course modern applications for whatever OS is your choice.
I think I still use my Amiga because it's fun and I know my way around the programs and the OS. For me it's quicker to do something in ImageFX than to figure out the same operation in Photoshop or Gimp.