Best places to stay in the Chicago land area, Downtown, Midway, O'hare, Oak Brook or any suggestions? Thanks for the help Guys & Gals.

You mentioned them all.  Most popular are downtown, O'Hare, Schaumburg and Oakbrook.  Take a pass on Midway.  Good luck.

Downtown is nice and has a lot of clientele there - this is where the hotels will be the highest. But they are also nice and very much worth it.  

Ohare is nice as well - you will spend less on Hotels and there is a fair amount of clients

Schaumburg is about equal to Ohare -as far as I have seen.  

Oakbrook - I dont have any experience with.  

Midway area- You didn't mention it so I figure your not considering . Which is good. Dont go there!  

Basically what the JoeDavola said.

......do split time in O'Hare & Downtown.