I have a bunch of favorite episodes but if I had to pick just five they would be
1. The Unicorn and The Wasp
2. New Earth
3.The Eleventh Hour
4. Doomsday
5.Rose

OK, here's a list of my top 5 Doctor Who episodes ever: #1 - The Unicorn And The Wasp (Doctor & Donna meet Agatha Christie)

+ There was a gay couple in that very same episode.

Here's another photo of the 2 holding hands, back in 1926!!

#2 - Tooth And Claw (Doctor & Rose meet Queen Victoria)

+ They're both knighted as well.

#3 - Fires Of Pompeii (Doctor & Donna visit Pompeii before the eruption of Mount Vesuvius)

+ Doctor & Donna save the entire family from a volcano.

#4 - Turn Left (both of my favourite companions, Donna & Rose, they finally meet each other)

Here's another photo of both of my favourite companions, together at last.

& finally #5 - Midnight (My idol Colin Morgan is Jethro Cane, a space emo boy from the future, the 27th century to be exact)

Here's another photo of Colin Morgan & David Tennant side by side.

+The Doctor meets Merlin Emrys! Here's a funny picture of both Merlin & the Doctor just for you.

Almost forgot. Here's another photo from The Unicorn And The Wasp. (Donna Noble meets her idol Agatha Christie in person)

Yet another photo of Doctor & Donna in Pompeii.

+ The 10th Doctor meets the future 12th!!

Hi! I'm struggling to limit it down to only 5 but i'll try....
1. THE DAY OF THE DOCTOR
2. BLINK
3. MIDNIGHT
4. VINCENT AND THE DOCTOR
5. THE WATERS OF MARS

:D