I would have to give a nod to Federal as well. The variety they have is admirable - a little for everyone and the quality overall is decent. They don't really have a "dud" line per se...even their entry level stuff like American Eagle is reliable and until recently affordable (though it's getting back that way). I run mostly Federal Syntechs and they have it in my preferred weight (147gr). But there are also excellent hunting rounds for various rifle calibers. And of course, they have a great HD line in the Punch, HST, Hydra Shok, etc. I will have to say though, that their shortcoming is in the .22LR market (just my opinion).
That said, I do also like Hornady, though as a whole Hornady more expensive. Almost for the same reasons I like Federal - the variety and the overall quality. The Superformance line is probably the best varmint rounds you can get across calibers (aside from the Nosler Varmageddons). They have a good selection of shotgun ammo as well. But my criticism of Hornady is the same as Federal's when it comes to a lack of quality for the .22LR market.
While this brand doesn't have as much variety, I have found their rounds to be consistently clean burning across calibers, and has a great cost/value proposition: PMC. Their Bronze line for 9mm and .223 have always been reliable as has their X-TAC line.
I may get heat for this one but I personally love Barnaul/MFS. Yes it is cheap and when it was easier to find, it was fairly reliable. You will never find a corrosive round in a batch and you don't have to worry about it like some Norincos. And it smells better after firing than Tulammo. I still look for and buy Barnaul on the secondary market if I can find it.
Love the more premium brands too like Sako, Lapua, but I am cost conscious so don't buy them often and when I do it's on the secondary market.
EDIT...Oh, and Black Hills...I so wish more of this was found in Canada. It is superb stuff. I would even go so far as saying I'd buy it retail at any price...well, almost any...