It's all about consistency, and Edge has it. Yardage is key for consistent scoring. Edge gets a ton of yards a game, so as long as he is not injured, he'll get your team 8 - 12 points each and every week on yardage alone. That's better than having to depend on a guy to get a TD each week to get him to 12 points. Any TD's he scores is a bonus (since they are luck anyway

). He's got to be one of the top RB's this year barring injury.
I would take Harrison. He's good for 4 digit yards and double digit TD's every year. Wayne and Stokley have the biggest chances of decline, mainly because someone is going to lose a decent amount of TD catches if Manning doesn't go for 45.
Clark is interesting. He could be huge next year because Manning likes to look for the TE. It might take a high pick, but it could be worth it. Think about it: between Pollard and Clark last year, there were 700+ yards and
11 TD's!
Say Manning goes for 35 TD's (high end for me). If Harrison gets 12, Wayne gets 8, Stokley gets 8, and Clark gets 7, that would still be pretty good. Probably not #1 numbers for Wayne, but decent numbers for Stokley and great for Clark.
At 30 TD's, Harrison probably gets 12, Wayne gets 7, Stokley gets 6, and Clark gets 5. That puts them back where they were before last year. That's the scary part about the Colts this year. If they regress to "normal," they won't be worth what you pay for them. But, the offense is better than 2 years ago and teams will still have problems with their ability. I just don't expect teams to lay down to them like they did last year and give up 3 TD's a game in the air every time.