Best Buffs, Healing skills, lowest damage (if you consider the DPS of Sentinel) and a very low attack speed. Medic is a very basic healer/buffer that almost any MMORPG deliver to your players. If you like supporting (believe me, it is fun!) this sexy nurse is your choice.
Medic is not made to attack and kill, but she NEEDS to do it right? The first tier skills has basic attacks, but they can deliver curious effects, like Knocking-out and Chakra damage. I don't really see a reason to get all of them, just the first four or five if you want the Knock-out one. Some may consider getting all to build a "Battle Medic" but she has better skills for that.
: Atomic Shots that reduce movement speed and do Knock-out. Great for Battle Medics, useless for support ones for the simple reason that you need all the skill points you can get, to use on her healing and buffs.
: The exact same problem of Tier 2. Those skills give DoT damage, and this is good on PVE and useless on PVP. One of those skills has LV 30 requirement, with hamper's even more their efficiency. Get it if you want a Battle Medic, along with Tier 2. Avoid it if you are building your Medic on the classic supporting path.
This is the Medic's main tier. Your lovely skimpy Nurse needs ALL of what's in here. But beware on what you want to your Medic. Healer's Kiss is mandatory, for both Classic and Battle Medics, because Medic has a very bad Defense and damage, and you will get your pretty face owned countless times if you don't spam Healer's Kiss every 2 seconds on yourself. This is for YOUR survival and good for PVP too. Of course, you can't take your time to heal ONE of your 30+ friends on a fast paced PVP battle, but you can heal half of them! Even so, that's why you can learn Veil of Healing, that heals much more HP, on a AOE range for all your allies on PVE or all that's close to you on PVP. Tt is not a bad idea to increase both at decent ranks. Restoration is the highest HP healing skill of the game, with the highest cost and the highest cooldown. Lazarus Blessing is THE ONLY REVIVAL SKILL of the game. Do i need to say more?
: The first two are mandatory Buffs. Great increases and with a enormous duration, and on top of that, they hit AOE on 6 people. They are great for you, for your friends on PVE and PVP. Veil of Critical and Detection are also great buffs, but their duration is much lower. Put at least 1 point each, and more if you feel like it.
: Another great tier with great Buffs, but all of them are single-target, so they tend to be useless on group PVP. But are great if you are more into PVE. Shift is a funny "utility" skill to teleport and get out of messy situations. Eradicate may mean nothing to you for the most part on PVE, because very few monsters deliver stats effects. This is not the case on PVP. Heeled Flair is the only one that i really see no reason at tall. Okey, it is a high Move SPD buff but why you need this? You can have a usage to reach your allies faster, so you can heal and buff them before they start dying, but it is a very specific usage for a skill. You will only have opportunity for that on PVE, most probably on dungeons.
Special info about buffs: A lot of players agree that spreading the points on the buffs is a waste, since most of Medic's Buffs are much more useful if you focus on fewer ones, raising then much more than spreading your points on all of then.
: Medic has a lot of Passives and their are much a personal option. You probably don't need any because of your great buffs (except, maybe HP Passive) but if you want something more permanent, get one or two, and focus on them. SP is a great choice, since Medic use a lot of healing skills and have a constantly need of SP. I disagree on getting Speed Mastery, because, as i say above, i don't really see a reason for why a Medic should run faster.