I use DiskMaster 2 (v2.6) with a few extra archiving features for xad, diskwiz, and unrar in the menu. This allows de-archiving almost anything I need. I have included the newest lha and diskwiz in a C directory (to be copied to the C: path) but NOT xad or unrar because of size which can be found on Aminet. Diskwiz handles .dms, .adf etc. with the default path asking for rad: since I don't use df0: anymore. Xad handles anything it has a driver for including .7z now (do not install XFD). It's set up for a 800x600x8 mode by default but can easily be changed with a text editor in DiskMaster2.prefs. Here's the link...
http://www.heywheel.com/matthey/Amiga/DiskMaster2.lha
I like old DiskMaster's gui more but having unrar would be good.
DOpus's gui looks better to me but didn't know that it's buggy =/
