Tough call for me. The Fall have had so many line up changes and phases that the different albums often have very different feels. Difficult to compare Grotesque, Witch Trials and Slates era with the Hanley middle period (pre and post Brixs) with the more recent (decidedly sketchy) stuff.
I think I'd probably go for 'Perverted By Language' ...or 'Grotesque'... or 'Code:Selfish' ... or or or or.... hell, I even have a liking for 'Reformation Post TLC'!!