First, get a full set of heirlooms. Second get into a high lvl guild for the fast track exp bonus.
From here you have 3 "quick" options.

1 death knights by far are the quickest because you skip 1 to 55 lol duh

2 pallys - one of the best fun to level *5 imo it goes a lot quicker because its so fun to play them

3 druids - best for gathering and thus professions imo I have a team of druids just for low level gathering herbs skins mining and another five set for tailor and alchemy. Mobility = quicker


With that being said I would wager any team would work but I would start with those 3, plus dks are pretty awesome now pallys always were and druids are still a ton of fun

Good luck!