Strata's pre Discworld (and I've never read it so I can't comment either way) and CoM and LF are 'practice books' essentially and like WWD I still read those two and enjoy them from the PoV of it being interesting to see some of the later 'stock' characters whilst they're growing up. LF in fact has some brilliant touches - the bits with Cohen in them are inspired and he doesn't change at all hardly. But they're not as good as the rest 'cos Terry was still working things out and hadn't got into his stride yet - I think for me that was achieved in Mort and he didn't look back after that.
Wyrd Sisters, Pyramids and Moving Pictures were all excellent and (aside from being biased and nuts about Gaspode) I still think the latter is wonderful because that's the point where Terry's really starting to show his true mastery of satire in making his most astute and pointed pokes at social idiocy
I don't really dislike any of the books he's written that I've read, although Going Postal didn't impress me that much and so I'm not too interested in looking at Making Money (Moist didn't appeal much TBH) and the Feegles leave me cold more or less and almost put me off Carpe Jugulum. Certainly I'm also not fussed about reading the Tiffany books either for that reason mostly - but also because I'm the sort of person that goes the other way when told 'You MUST' do something... but I'll probably give in to the glowing recommendations some of you have given for those 3 books... eventually!