Soraka-Since the patch change to healers, she's a bit unreliable now as a babysitter/support. She can still support, you'll just find her to be a fairly weak support.
Taric-He was quick before. Now it's painfully long requiring you to throw yourself in danger to get it back up. In teamfights, it doesn't matter so much. He wasn't that affected by the patch, but you just have to build him like you did before, and not throw out heals as much.
Ult: Toggle: Taric emits brilliant light, healing himself for 30/40/50 (+0.2) a second and increasing his and nearby allies' attack damage by 30/60/90 (half effect for nearby allied champions). The cost to sustain Radiance increases by 4/7/10 each second.
Janna: According to top players (Elementz only, really...) Janna is currently one of the best supports to pick, due to a nice knock up spell, shield, and slow. She really just controls the battlefield.
Karma: Eh. Never really heard a lot about her.
Zilean: So totally not biased here (I love Zil), he's an extremely strong support in terms of zoning, harassing, and a great asset in team fights. His ult is godly if you can throw it out fast enough. I consider Archangel's core on him because of his W spam.
Alistar: Is actually one of the best right now. Knock Up/Stun and Knock Back, with a heal and the ability to nullify a lot of damage, he's pretty nice right now.
Orianna: Epic support with her haste/slow and her shield. Excellent zoning because of the Ball. Ult can be game-changing. Orianna es #1.