Its a close call. Spurs have 3 titles this decade and the LAL have 4. (they won it in 1999-2000- that counts for this decade.) titles. As mentioned earlier the LAL have been to a total of 6 finals.
The whole spygate/Mangini taping does add a little tarnish to the legacy, but the on the field performance is what matters...
1. Lakers 4 titles, 6 app
2. Pats 3 titles, 4 app
3. Spurs 3 titles, 3 app
4. Yankees 2 titles, 3 app
5. Red Wings 2 titles, 3 app
My .02$