I always wonder how this plays out at the LBS. They bring you out three pairs of shoes, you try them all three on and one fits like a glove. Then what? You say, uh, these fit great but I'm gonna need to think about it a little.
I bought mine at REI. They had that 20% off sale on one item so I picked up some Shimano R086 Road Shoes for a total of around $90 out the door. They were really helpful with letting me try on different models and sizes and since these were the first road shoes I had ever purchased I had no idea how they were supposed to fit (an inch in the toe, completely snug, velcro tight as possible or rachet loose as possible, etc...)
I think online I could find them for $10 less but it just wasn't worth it.
The problem comes in when you're trying to purchase $450 Sidi's and can get them online for $250. Moral dilemma time.
I purchase my Conti 4000S tires from PBK cause they're $68 a pair instead of $68 a tire. Plus I have never asked my LBS about them or tried them on. I get all my advice here at Bike Forums which says extremely little about my state of mind.