Who to buy next?

Soo, I'm getting up there in IP, i have around 4800 right now. I'm wanting to buy a strong champ that can be used in ranked play. I was thinking about fizz, but not sure how he handled the recent nerf. I can do pretty much any lane, but mid is my strong suit (I play A LOT of Ahri.) Just wanting some suggestions on some good champs to have would be. ADC isn't really my best position, and neither is jungling, but i can do both decent at least. Any suggestions would be amazing :)