There seemed to be several threads devoted to favorites, but there have been more than a few series that had huge marketing and giant budgets (Golden series) that TVB puts out every year, but some of them I just can't get into:
The Bund - either version, stupid reason but i am slightly turned off by the women's costumes and the flouting of machine guns
Threshold of an Era (Part II) - overall, i enjoyed the entire series, but taken apart, part II is no where near as good as part I since the plot falters a bit.
Triumph in the Skies - very good, then all the guest cameos (oh comeon, Twins reunion?) and really draggy ending
Dae Cheung Gum (Jewel of the Palace - i know its Korean) -- the series finished well in the second half, but the first half spent like 6 episodes on obsessing over how to cook the gold chicken or whale...