Frozen Corn is for Losers.

I have this strong memory from more than 10 years ago of watching the PBS cooking show that starred Jacques Pépin and Julia Child. There was an episode where they got into a semi-heated argument about whether or not it was ever appropriate to use frozen vegetables. Julia believed that there was no circumstance under which it was acceptable to substitute frozen vegetables, but Jacques maintained that frozen peas (particularly the baby or "petite" ones) were OK to use when you couldn't find fresh. At the time I agreed with Jacques, and remember thinking to myself "I would say corn falls into that category, too." The more I've cooked with and enjoyed fresh vegetables, though, I find myself drifting over to Julia's side of things. (After she'd tasted Jacques' frozen peas, by the way, Julia admitted that maybe frozen peas were OK to use if you had absolutely no other options...)

I still use frozen peas from time to time, particularly in dishes where the peas are likely to get soft anyway (like when I make paella or Cauliflower, Chicken, Potato, and Pea Curry), but when peas are the star (like the peas delicately cooked in butter that sit atop the Pacific Northwest Salmon Chowder that I make from Jasper White's brilliant "50 Chowders") I would rather omit the peas entirely than tarnish my dish with frozen...
Getting back to the corn: I love corn. In my youth, a bowl of microwaved frozen corn with a sprinkle of salt was a delicious snack. Obviously it didn't compare to a grilled ear of fresh corn, but I felt like it was a pretty good substitute when fresh corn wasn't around. I used frozen corn in my cooking without giving it a second thought... Then I moved to California, started hanging out at a farmers' market, and realized that I could get copious amounts of fresh corn dirt-cheap when it was in season, so I started using fresh corn instead of frozen in my cooking. The recipe that changed everything for me was a Spicy Black Bean Soup, which got a little extra texture from, among other things, some fresh corn stirred in at the end after the majority of the soup was puréed. I loved that soup, until I made it once when all I could find was frozen corn. I still remember my first bite of that frozen-corn-substituted soup, even though it was over 4 years ago. The corn was mushy and soft, lacking that brilliant bite that fresh corn brings to the table. I felt seriously angry each time I bit down into a stupid piece of stupid mushy frozen corn, and ended up not eating most of that batch of soup. I made a promise to myself that day: Never again.
I have fresh corn on the brain today because I made a big pot of Chicken Tortilla Soup this weekend using 5 ears of fresh corn (shown above, freshly sliced off the cobs) from the totally awesome produce store in my neck of the suburbs. I'd made this soup for years with frozen corn (it's a great soup to make primarily from pantry items if you use frozen... I'll post the recipe one of these days...) and it was pretty good, but it is absolutely fantastic when prepared with fresh corn. Every bite that contains a piece of corn is seriously a joy to eat. With the reminder from this soup (which I was crankily thinking I would have to make with frozen corn before I stumbled across the fresh), I can't see myself cooking with stupid frozen corn ever again. I even used fresh corn the last time I made my mom's awesome Chicken Enchilada Casserole (an old-school casserole recipe featuring cream of mushroom soup and everything, written in the days when they would never dream of having easy access to fresh corn), and it completely elevated that dish, too. In hindsight, I don't know why I was surprised to discover that Julia Child was right all along...
In summary: Fresh corn. Accept no substitutes.
Also: Never doubt the near-infinite wisdom of Julia Child.