SnapMan said:10.6.7 to 10.6.8 was the only update that seemed to cause a lot of people issues and that has been resolved.
Personally I have updated 10.6.3 to .5 to .6 to .7 to .8 to 10.7.0 without difficulty.
So, if it is a work machine that you depend on, wait a couple of days or a week, check the forum/blog and then you can go for it if no one has reported problems.