I'm a Coca-Cola devotee myself. I think McDonalds is great and it's ubiquity the true joy, but if I'm walking around in a neighborhood I generally prefer getting it from a good bar. I feel like they keep their Cokes a little extra syrup-y because they're going into drinks.

Another perk is that sometimes they don't even charge me for it. :)

Colder means your taste buds are numbed, so you taste less. There's a nice story of how Guinness wanted to sell more in UK pubs. The brand was solid but people didn't like the bitter taste. So they invested in a special cooling thingamajig to make it "ice cold", marketed the hell out of it and, boom, major sales.

Of course I'm one of those British beer drinkers who insists on having it at room temperature so you can actually taste the beer.

I've often heard that Coke at McDonalds is the best and I couldn't DISAGREE more. As for any cola, I think getting it from a fountain machine (meaning not a bottle or can but served from a syrup mixing machine) will produce the best cola, however I think fountain Coke at McDonald's is watered down and the least flavored of any place I've had fountain Coke. The interesting thing is how consistent it is. Kudo's to McD's for that, but it doesn't resonant with me at all. YMMV.

I think the wider straw bit is a big part of it. It's like, BAM, flavor assault with one sip.

I am a Coca-Cola fanatic. I have been since my days of growing up in communist Bulgaria, which was the first (and only, AFAIK) Eastern Bloc country to bottle Coca-Cola locally.

In the US, Mexican Coke (made with real sugar) is the best Coke you can get. Many McDonald's franchises cheat by watering down the mix -- using less of the more expensive Coke concentrate and adding cheaper syrup (which explains the more syrupy taste of McDonald's Coke).

I had a McDonald's Quarter Pounder® with Cheese meal yesterday. The Coke was as described above -- watery and syrupy.