Im a Swordmaster Tactician on mine; picked Swordmaster over the Iron Vanguard paragon cause i really like some powers that path has and Tactician because i feel that choice provides me with most utility for the group (buffs and so on) as well as good enough tanking potential and survivability for myself.
At-WillsWeapon Master's Strike -- I use this one as main at-will over Cleave because it has a larger AoE, can hit a lot more mobs with it easier then with Cleave. This one is only available to the Swordmaster paragon path.
Tide of Iron -- This one is my secondary at-will. It's great for regenerating stamina with it (u get 10% stamina on each use) especially if u have the bonus for it on the main hand weapon artifact too(if u have the bonus on main hand weapon artifact for this too u get an additional 8% stamina after use) and it also debuffs monsters lowering their damage resist (this debuff only applies for yourself, not for allies too).
For multi targets (lots of adds and monsters)Enforced Threat -- Basically the most useful encounter when it comes to grabbing aggro fast and easy on many monsters at once. It also regenerates a portion of GF's stamina over time.
For final bossesCommander's Strike -- This encounter buffs the dmg on next encounter used on a marked target for all your allies by quite a lot so it is a good choice in boss fights if you're going for more buffs. Can be switched instead of Enforced Threat.
Encounters that never leave my bar in group content(dungeons)Knight's Valor -- U can toggle this on and off, should always be active though. Its pretty much a protection aura over your party that lets u intercept half of the damage they take. It's incredibly good cause u can protect the more squishy people in your party and soak up half of the damage they take but it's also risky for the GF cause it can get u easily killed especially when u aren't that well geared early on. U need to be careful with it and hold shield up often when u are using this when u think people will get big hits of damage.
Into the Fray -- This is a party wide buff that can also be improved through a tactician feat (Inspiring Leader). There's just no words to describe how good this encounter is. It provides yourself and the team with increased damage (at rank 4 it gives everyone in the party 30% damage buff), it increases movement speed by a lot making it easier for everyone to run out of reds fast or position quickly and such, it increases AP gain as well as providing all with a small amount of temporary hit points. It also regenerates a portion of stamina for the GF over a few secs time.
Class features(passives)Guarded Assault -- This passive reflects up to 20% of the damage u receive when u block hits but no more than 15% of your max HP (damage reflected is calculated before the resistances are applied to the received damage). The advantage for using this passive is not only the dmg reflect but also that if u use the offhand passive bonus for this it can also proc Crushing Pin feat each time u block attacks debuffing the target(s) (target takes 10% more damage from everyone for 3 secs) making this extremely useful if u use that feat from Tactician tree.
Steel Defence -- This passive is part of the Swordmaster paragon path. It makes the GF totally immune to any damage for a few seconds (3.5 secs at rank 4) right after using a Daily power. Can be really useful in saving your life in tough situations if timed right.
Steel Grace -- This passive is an optional one i often use instead of Steel Defense one when i feel i don't really need that to survive fights. It provides a bunch of useful buffs to the GF increasing the movement speed, deflect chance and critical chance by certain percentages (at rank 4 this passives grants 17.5% movement speed, 5% deflect chance and 5% critical chance).
Daily PowersFighter's Recovery -- This daily never leaves my bar for group content. It's really good if u find yourself low on hit points and need to heal up quickly. It gives u a HUGE lifesteal for a few secs after activating it, just hitting a few targets after u use it will get u to full HP in no time. And it also has a very fast casting animation which makes it good for procing "Steel Defense" passive fast. If u use Guarded Assault passive the damage u reflect when u block hits also makes Fighter's Recovery proc thus healing u each time u block and reflect damage.
Villain's Menace -- This daily is a self buff that provides the GF with CC immunity, increased damage and damage resist. It's pretty good in most situations but it has a slow casting animation. Really good in fights where u find urself often CC'd and knocked around and such like for example in the Lostmauth fight.
Crescendo -- This daily is a straight forward single target damage daily stunning your target and leaving them prone too at the end. Quick cast time and good damage. It's part of the Swordmaster paragon path as well. I usually switch between this and Villain's Menace one if i need some single target dps.