Coming from a Chicago homer, Hester is basically going to be the WR4 or 5 for the Bears.
First with regard to him at receiver, Berrian and Muhammad are WR 1 and 1a, depending on which way you put them in order, then Mark Bradley is WR3, followed by either Rashied Davis or Hester at 4 and 5. Bradley is more talented than Davis or Hester, as a receiver anyway, and will likely get quite a few more reps in any 3 WR packages (provided he stays healthy). Hester will be run out there a handful of times a game at receiver, and they'll probably try to get him the ball in space, on short routes, WR screens, or a reverse, hoping he breaks one with his playmaking ability. He'll be used as a decoy too, plus they also might use him to stretch the field occasionally, but I think less than most are guessing. Berrian is already the established deep threat, and has a great ability to find the ball and outjump the defender (making Grossman look good). That's something that will take time for Hester to develop.
As for his return game, the fact that your league would reward any return TDs gives him a bit more value, but still not enough to really warrant upgrading him much. There's no doubt he's got gamebreaking ability as a return specialist, but are return TDs something you really want to rely on. You're throwing darts at that point hoping you get lucky and catch one of the 3 or 4 games he might get a return TD.
Keep in mind the Bears also drafted Olsen at TE, and want to keep Desmond Clark in the mix since he had a career year last year. That's a lot of looks to share overall. Hester is not going to be a receiver that puts up any kind of consistent numbers, but he may be a big play threat. I still don't think he really warrants roster consideration, except in VERY deep leagues, if at all.
Also, you never know, David Ball might end up in the mix here as well at receiver. But I don't think anyone beyond Berrian or Muhammad should ever crack your starting lineup, and don't see any of the other receivers really being roster worthy.