Zeraph

If you want a great defense against crazy annie ganks, get banshee's vale. She can only stun every 5 spells, so her combo is set once she gets that ready. Which means she can't knock it off with her quick casting spell (or she can but she'll waste her stun). After that you only have to worry about a very close casting cone which she shouldn't be able to get close enough to you since she didn't stun you, and tibbs her ult, which is well an ult and she can only pull off every so often.

She could of course, wait till 4x spell energy to knock off the vale, but then you'll have plenty of warning.

Sorry, but I have to brag a little. I'll probably never play this good again :P I just had an amazing game with Kat. I was so focused, got two quadkills (actually killed all 5 of em but apparently one was a few seconds too far apart to count for a pentikill) in a row! We were pushing around lvl 16, killed em mid, then when they respawned we had another fight at their inhib and did it again! Best game I've ever had. So damn close to that elusive pentikill though ><

Best part was I pulled this off against decent elo players, they had 2 30s (the rest 20s) on their team, several stunners, no feeders, a blitzcrank (i.e. kat'sbane) etc. Even with that push the game lasted another ~15 minutes. Ended the game with 24/4/11 ~40 minutes. Next highest score was 10kbs!