Ooh, I saw this idea on the Digital Spy forums and it made me wonder what my answers would be, so I'm thinking aloud here if that's OK 
Favourite dance ever of each type [disclaimer: I have only been watching since Harry Judd's series.]
- Cha Cha Cha - Danny & Oti
- Salsa - Louis & Flavia
- Samba - Danny & Oti
- Waltz - Abbey & Aljaz
- Viennese Waltz - Danny & Oti
- Foxtrot - Debbie & Giovanni
- American Smooth - Danny & Oti
- Quickstep - Harry & Aliona
- Tango - Jay & Aliona
- Argentine Tango - Debbie & Giovanni
- Charleston - Sophie & Brendan
- Jive - Jay & Aliona
- Paso Doble - Alexandra & Gorka
- Rumba - Jay & Aliona
- Showdance - Louis & Flavia
I struggled with the foxtrot because none of them really stood out for me, and struggled with the Charleston because I LOVE Georgia and Giovanni's too. In fact, I'm still not sure which one I've rewatched most...