You might want to check the Aminet for a more up to date version of Directory Opus as version 4.12 was made freeware some time back and is still in development. A great piece of software that no Amiga should be without.
If you want to upgrade your Workbench software then there's several routes you can take. If you're stuck with WB3.1 then you could try NewIcons, which brightens up the stock icon set enormously, or you could purchase OS3.9 which is the most recent released OS for the Amiga. You'll get an upgraded icon set, AVI player, MP3 player, support for drives greater than 4.3Gb in capacity and an upgraded set of datatypes/libraries amongst other benefits.
If it's eye candy you want then you could try downloading Magic Menu for all kinds of nice drop down menu effects, Visual Prefs to play with the look of the Amiga's standard GUI, ReqAttack to add some nice animated system requester messages and Birdie, simply because textured WB windows look soooo cool.
That's the OS sorted out. For imaging software you could try Perfect Paint, which is also freeware. Photofolio is a thumbnail picture viewer that comes in handy and there are replacements for the standard media viewer; Visage and Picshow being two.
