there are way too many options for the supported archive types. .tar.gz is enough for the common user, as it's the common extension anyway. there are 10 types in my combobox atm, but 5 of them would be enough. such things as .tar.bz or .tar.Z are barely used. to create an easy to use app even for users new to linux that want to have a gui like winrar for example, there are simply too many options to confuse them. .tar.gz .tar.bz2 .tar .zip .rar should be enough. plus make .tar.gz the default (or let the user choose in the preferences in the future) because .tar doesn't use compression.
Viewing the (translatable) mime-type description should reduce the confusion, while it will still allow users to create archives of every supported type.
Selecting which ones to show won't be part of 0.2.0, but i agree something like that should be there, with squeeze eventually supporting over 10 different mime-types, this will become messy.
squeeze is not maintained anymore, closing.