Supposedly people with diabetes have slightly shorter life expectancies, because having the condition makes you more suceptible to, well, everything, pretty much. However it's hard to say really. You can look at the average age of death for people with diabetes in 2005, but you've also got to remember that a lot of those people would probably have had the condition for many years and would initally not have had the benefit of new monitors and insulins. Having said that, there are quite a few individuals with diabetes who are now in their 80s and 90s, having had the condition for over 70 years.
Basically, your life expectancy is dependent on you. Keep getting good A1cs and you pretty much negate the effect of having diabetes. The flip side is also that, as a person with a major medical condition, you're probably going to pay more attention to your health and see doctors more regularly, so you might even end up with a longer than average lifespan.
Bottom line is, if you look after yourself, you'll probably make it to the late 70s/early 80s. If you don't, you'll probably be lucky to make it past 60. As ever, the ball is in your court.