Which bits I find most worthwhile? I take that not to mean brands, as for the most part there is not much difference for hobbyist use.
Yes, Larry, many are orange but that is not a requirement. And yes, I have a ton of them. Being the Router Lady had its perks.
But it also taught me a bunch about what it is that is really helpful to have on hand.
To Rob's question: best for whatever it is that I am doing. But I would not be without a chamfer bit, a round over bit, a very short 1/2" mortising bit, a 1/2" trim bit, 1/4", 3/8" and 1/2" 2 flute right hand twist end mills, and a rabbeting set. Those are the most useful to me. Your list may well be different.
My general philosophy is get the one I really want and don't look back. Also, no sets and no gimmicky bits. Both are expensive and useless.
And finally, when they get to the stage that I need to touch them up with a diamond card file to finish the job at hand, it is time to get a new one. They are consumable items, just like sandpaper.
Conversation goes like, "That's the last piece of wood you burn!" and clunk, into the garbage can. Life's too short.