Varus: Building phantom dancer x2 is a huuuge deal for varus after you get that infinity edge you really want. Last wishper ofcourse for the high armor pen, and abit ad.
Alot of guides and youtube clips says that trinity force is a really needing item for varus just for the W and R.
But I prefer highly to not get that to Varus.

Leona: Playing as leona is great fun with all the stuns.
Buying wards is ofcourse a great deal.
Alot of supports starts with F-Charm and 6 wards or something, but if you buy boots of speed will make the early game easier to get to the bushes 1st and stuffs.

Leona and Varus is a great team alot of cc and high damage.