The most obvious pick is Chris Williams because he is basically guaranteed a starting position at left tackle unless he's injured or something. This is a good way to start building up a young offensive line, and you can't have enough good offensive lineman, everybody knows that.
Depending on what they do with Benson, Forte will be an impact player for the Bears this season. Now I remember watching him play a little bit last year and I remember he had over a 300 yard game with like 4 or 5 touchdowns. I don't know much about his gamebreaking speed but he looks to me like a better version of Thomas Jones. He will push Cedric for a starting spot come training camp and I wouldn't be surprised if he got it.
Marcus Monk is someone who can come in without expectations because he is a 7th round pick. He's tall and fast with a good body to catch passes in the redzone. I could see a position where he could come in later in the year as a number 4 receiver and make several nice catches along the way.
I'm not really sure about the Bennett kid. I've been reading alot about how he reminds people of Hines Ward because he's got the same body type and is a possession receiver. He may come in and compete for a starting spot from the get go, and there really isn't that much competition with the lack of quality receivers on this team. Booker and Bradley are 2 guys I think that will definitely have starting spots coming into the year with either Hester, Lloyd, or Bennett being the 3rd guy.