Actually I meant it gets dumber AFTER the Freiza saga. The end of Frieza saga was definitely teetering on dumb too with the amount of wasted time involved. They could have cut out at least an episodes worth of stuff in that last fight. Still I thought Frieza was awesome, he's a sadistic and deceiving little shit. After that though the series really starts to go downhill, especially the first half of the Buu series.... My god is it annoying. Although the last 10 or so episodes are excellent.
Edit : Original Dragonball is also awesome, it's more of a story and adventure, rather than a series of fights. It's a change of pace to say the least. Goku is always awesome though.