I'll estimate I can crack 100 at my very fastest but I would also say that's a very rare thing, I would say my 'good day' fastest serves are 85-100. Mdshahid I believe can crank it around 110, or at least 100 a little more frequently than I can.
These are pretty rough estimates I would say, wouldnt' be surprised if I was way off. When I started playing tennis, a totaly newbie, I used to play with this kid who used to think he was all great and used to brag about his serve being clocked 76 mph. And I never had trouble handling that serve back then and I know for sure I was able to hit faster two-three years later. Since then my form has only improved (and so i need considerably less effort to achieve those speeds) and I do at times shoot for some faster serves just to make sure I can still do it (I don't worry about speeds much, I have mostly been using my good form to keep stress off my arms and place balls well) and I know I can hit it well beyond what I could from back in the day.