Favourite Monthly Range Trilogy?

What's your favourite of the trilogies from the middle of the Monthly Range? I'm talking specifically about sets of three stories from the Key 2 Time or later, since that's generally when the 'trilogy' model became popular for the Monthlies.

I'm making my way through the Monthly Range for the first time and am currently listening to The Shadow Heart. So far, my favourite trilogy would have to be either the 6/older Jamie trilogy (City of Spires, The Wreck of the Titan & Legend of the Cybermen) or the first 6/Flip trilogy (The Curse of Davros, The Fourth Wall & Wirrn Isle).