Soon I'll be playing ranked games and I was wondering what champion would be a good pick for solo top. I was thinking Vladimir but I'm not quite sure if he's the right choice. I want someone that's not easily countered and can sustain in the lane for a while. Please reply with your suggestions on who you think I should get.

I think Mordekaiser can either mid or solo top

Yorick is quite a fine Solo Top choice. Massive harass and zoning. Though watch out for ganks. Riven is also a great choice due to her pretty strong early game damage making her a force to be reckoned with. Mundo can be quite fun as well. Can build super tanky yet still hit like a truck.

For Mid, Mordekaiser works nicely against certain matchups but burst/DoT champions really hurt him a lot.

I really am not too sure with Mid as Solo Top is my favorite and niche role.

For mid, Malzahar and Karthus can be quite fun to play, and are powerful in their own right, and devastating in teamfights (although they do take some skill/time to master).

I love going solo top with Nasus. Keep farming that Q whenever you can, get a tanky setup and you can easily lead your team to victory, though I am not sure he is viable in ranked games. :/
As for mid, I really like playing Anivia for her stun and her wall can seriously hurt your enemies.
I don't play ranked games, but I think Anivia should be a pretty good champion for ranked games.

I may be wrong, but I just want to point out that Morde might not be the best choice, since he has no CC, nor does he have any escape mechanism, which is realllly annoying.

Top: Yorick,Rumble,Renekton,Riven
Mid: Ahri,Malzahar

Mid: Fizz

Top: Olaf, Singed, Nasus

Before the new patch I would say Cho'Gath but after this unreasoned indicator on Rupture I think he isn't the best top anymore, though still in the top of my list.
I guess Renekton, Garen and Olaf can be very destructive in the right hands.

About mid... I have no idea, I never go mid (random guy always call it).

Bump. Edited post.