I understand that is what the advertisers and companies believe, and I'm sure they have oodles of studies to back them.
Personally, I don't browse. If I want to buy something, I go in, buy it, and leave. If I were a habitual browser, certainly the commercial I saw, or, even worse, was forced to watch, would not induce me to buy the particular item. If anything, I would avoid it out of annoyance.

Tv spots for upcoming movies and ads introducing new products are the only two I can think of that could directly lead to me buying something.

I will even go as far as to try to watch the commercials during my favorite shows like Lost, 24, Survivor and Teh Office so as to lend support to the companies paying for these shows to air. I am not saying that I will end up buying their products but at least I gave them a chance to sell me on it. Another thing, commericals are not all that bad to watch, for some are quite entertaining I think.

I'm the same, there are quite a few items I wont buy due to commericals. Soda commercials don't sway me either, I make a point to buy the store brand now days. Sure it's cheaper, but wasn't the deciding factor.