I agree with metaldude; a lot of uncertainty in St.Louis's forward core. I view them as a lesser version of the Flyers in that they have about 8 guys who deserve to be in the top six. McDonald will be key in the development of the younger Blues, but they might pass him on the depth chart along the way.
Laich has the advantage of riding the AO, Semin and Backstrom trains
The McDonald types, well I seem to be too slow to get on their wagon. He's definitely top 6 forward or not in the NHL. I was afraid of him, after he left Anaheim, thinking he was dependent upon Selanne to achieve at the 80 point level. The asking price was too high at that time too. He went to the Blues and achieved at the 55 point level, except for that 1/2 season when he was looking very similar to his Ducks days. Thus, I wonder about him for up to 70 points. However, I only believe in him for 55 points. Like last season. At age 33, there's not much time left for him to burn me!
Laich has shown steady growth throughout his tenure in Washington. He out pointed McDonald last year and is only 27. I'm not so certain that his offensive skill set really competes with McDonald's, but he's in the right spot at the moment. We'll get a real good feel for what the Caps think of him when contract renewal time comes next spring. No reason by my thinking to expect less than 60 points this coming year. We also get to wonder if he continues to rise on up! He spends significant time with some pretty nifty people. He's also considered a winger in many pools (one of those split kind of guys C/W). At the moment he's also got the better cap hit. I suspect he should end up $2.5 or $3.0M after his contract renews.
I'll take Laich, particularly if he has winger status. His age factor and continuing uphill climb give him the edge in my opinion. If McDonald was a winger & Laich a centre, and I needed a winger. I might consider taking McDonald. Generally I'd take Laich.