I have a void and arc shotgun, then I have a solar sniper and fusion rifle (based on what I need). I keep different primaries mainly because switching them around keeps the game fresh. Heavies are a little trickier, because I have one rocket launcher that's just my favorite, period, but just last night I got the Raid machine gun, and that thing seems pretty amazing, might actually replace my rocket launcher once it's fully leveled.

But yeah -- at first you feel like purples are impossible to get, then once you get your first one (which I did via Vanguard rank), you start getting a fairly steady stream after that (as long as you're doing weekly challenges like the weekly strike, weekly nightfall, and Raid).

A dude in my party unlocked that Raid scout rifle the other night and sheeeeeeeit I'mma keep whooping Aetheon until that thing drops for me...