We find those achievements of the "do the entire game again, only on ludicrous difficulty"-type to be quite annoying.

Its much more fun with achievements based on funny combos or easter eggs or other unusual circumstances. Collect [i]n[/i] elven left ears is a decent one. Chop down an entire orcish horde while wearing a blindfold, a loincloth and wielding a red herring isn't.