The market price appears to be pretty close to Bitcoinaverage.com. I think they are a little bit high yet, Blockchain.info is a little bit closer to reality. As long as we know what the market rate is, it doesn't much matter. Vendors calculate their price in fiat, and divide it by the market price, so either way, the price ultimately paid is correct. Or at least that's the way it should be done to keep it fair to both buyer, and seller, IMHO.
Current markets and Blockchain.info at time of posting:
Silk Road: $406.19
Blockchain.info $395.90
Sheep Market: $393
BMReloaded: $394