The best way is to work out your own personal carb levels, bearing in mind this will vary during the day
http://www.alt-support-diabetes.org/NewlyDiagnosed.htm
My experience in various forums and newsgroups is that the majority of successful people seem to cluster around the 50 - 150g bracket, probably most towards the lower end. Some need to go down to Bernstein/Atkins induction type levels and a few can do substantially more than that
Also it can change over time, for example I can do about 15g at breakfast which has never changed, but I can push from 30g up to 50g in the evening now without too many problems (I don't do it often) but my late night tolerance has actually come down again so the distribution over the day has changed but the total quantity remains about the same. Christmas dinner also showed that a late lunch has an improved tolerance similar to the evening levels.
I tend to aim for around 60 - 100g depending on activity levels, if I do too few carbs at the wrong time my liver has an annoying tendency to be helpful and shoot me high so paradoxically sometimes more carbs lead to a lower BG (this has also improved over time)
That's why I push testing a lot, especially at first, so you can discover your own system's flight envelope