The default is Celestial Nighthawk for GM+ PvE, but you can go Shards of Galanor to burn through easier content faster. Weapons are whatever deals with Champions, but Precision weapons are preferred for Nighthawk builds. Heal Clip + Incan is the go-to combination here for general use. In PvP things are more complicated. Solar Hunters aren't that great in the Crucible because their neutral game is weak. Most of the power is going to come from you Super, so you can stat your build to try and get there faster than other players. The other option is to work towards a "cheese" build, so something with Athrys' Embrace or a TTK shift with Radiant. Frostees/Aeon's with the Radiant dodge provide surprisingly high uptime on the Radiant buff but it's a different kind of playstyle.