You are going to make yourself crazy by overthinking this thing.
Get the 18-200mm and relax. You can leave one lens on the camera and do most everything you want. There is lots of time to get additional "specialty" lenses later when you really figure out what you need and want. The 18-200 will give you great flexibility without changing lenses all the time.
The 50mm is worthwhile because its cheap, optically good, and shoots well in low light. Its not necessary now, and you can add it later when you are ready.
If you go with the 70-200 you can't even shoot a group photo (the team, a kid and his buddy) without changing lenses. The 50mm is even too long for many indoor or close shots. I leave an 18-200 on my 30D most of the time, and use it all the way from all the way wide to all the way long. If I have time and need the very best possible shot at either extreme, I change lenses to an expensive specialty lens (ultra-wide zoom or fast telephoto zoom), but sometimes the shot opportunity is gone before you can think about changing lenses.
This will not be the last time you buy lenses in your life. To me, it makes the most sense to go for max flexibility up front, then add capability in certain areas as you find you need/want it.
Now shut up and buy something.
JD
P.S. just kidding about that last line