Personally, I wouldn't match it. First, the Trek dealer agreement forbids online/phone sales so I know the only way the guy is going to sell you the bike is if he doesn't care about the risk of losing the line.
Second, I know you're going to pay half the difference in shipping, then you need to assemble it and properly tune it, and hope nothing got damaged in transit. Given that it's your first bike, I don't see much benefit for you. Does your local shop offer any free service after the sale or discounts on accessories purchased at the same time as the bike? That would seem to me that it would be of more benefit to you than saving a bit initially.
Oh well, that's just my thoughts as a local bull$hitter. Glad to see people are growing up on here.