I'll start with my age as a frame of reference here. I'll turn 40 this summer, and IMHO, Lego today is at it's high point for me. The modular city sets are brilliant. Star Wars is amazing for young boys. (My son is 9). My 5 year old daughter LOVES the collectible minifigures, and builds with her brother daily. We go to the Lego store monthly to look and pick up odds and ends. I can't wait for the Cars sets. I already have the Queen Anne's Revenge, and look forward to the Black pearl.
Yes, I love my childhood sets like the Galaxy Explorer, and they make me smile every time I see pictures of them. I just think the color palette and parts selections are better today. And the set designs are pretty good, too.
The low point? The late 90's when I came out of my Dark Age. Insectoids? Blech. UFO? No thanks. I have an entire bin STUFFED with mostly useless brick junior pieces.
The worst part about Lego today? My credit card statements.