Actually I swap talents out depending on what I'm doing. If I'm patrolling or fooling around, I stack agility. If I'm raiding, I prioritize armor and recovery. PvP, depends on how I feel but mostly I stack agility be mobile. However, I also tend to use Fusion Grenade in PvP, but that or solar works. I'd like to mess with Firebolt. Never tried it before.
I pretty much have Fireborn on all the time, but I'll sometimes use Radiant Skin.
Focused Burst and and Balanced Glide? Up to you. I stay with Focused Burst to get huge hangtime.
Flame Shield is my must.
Radiant Will and Viking Funeral are both good. However Viking Funeral + Solar Grenades + Touch of Flame is pretty damn nasty. This allows your grenades to do their initial damage as well as produce DOTs on enemies even if they're running out of the grenade blast radius.
Gift of the Sun makes Radiance radiant IMO. However, like I said above, a case can be made for Touch of Flame. Angel of Light is okay, but I think it lacks compared to the other two.