Spar, you should be fine on $50 Euros a day. That's about the going rate in terms of budgeting most of Europe on a daily basis. If you decide to visit Western European countries like France, Germany, England, etc... you'll be just right. Switzerland can be a doozie, so be careful on the budget there.
As far as Central and Eastern Europe, you'll be just fine. In fact, it could be more than enough
Your biggest expense will be traveling fares from country to country and accommodations. Get that out of the way and it's all good B)
But where exactly will you be going to?