Personally, I don't think it's essential to own a scope. I went two years of hardcore learning and playing around with just a RadioShack firestick and RadioShack DMM.
I bought my first logic analyzer to help me solve a specific problem. I bought my first scope to help me solve a specific problem. I bought my second scope to help me solve a specific problem. When I don't have a scope problem (and for me it's fairly rare) I could care less about a scope. Both these scope were worth the money, because the problem was worth the price.
It's better to have a purpose, in some ways. That justifies the purchase. Plus when you're having some difficult problem, it's nice to buy a new piece of equipment to set up and learn, just to shake things up. And to temporarily put the actual problem aside for a bit. To forget how out-of-your-league you actually are, for a bit, and to feel like you're automatically one step closer to the solution simply by having this new equipment on your bench. Then you get to turn work into playing with something new.