It's been so long since I've seen any of these that I only have vague memories of them. I voted for Enlightenment as that's one with many imaginative concepts I remember - strange Immortal super-beings, yachts floating through space. Great stuff!
I remember Kinda and Snakedance as being particularly strong once you got past the dodgy snake effect.
The Five Doctors was very memorable. It was great to see all the old faces and I've probably watched that one the most times.
I also enjoyed Planet of Fire. I'd recently been to Lanzarote so the location struck a chord and, of course, it had Peri in a bikini. What more could you ask for