I know this is an old post but I couldn't find an earlier thread on the topic. Here is my opinion on the matter of collarless shirts with a sportcoat. I think a t-shirt under a sport coat / blazer is a matter of taste faux-pas. A non-solid color t-shirt (exceptions made) or logo under a sport coat / blazer is a crime. The alternative of course is the collared shirt. However... This CAN be too dressy, or perhaps not PERFECT for the situation, the utimate goal of STYLE. The alternative I believe is a light, long-sleeve shirt, WITH THREE OR FOUR BUTTONS FROM THE NECK. I find this classic, but NOT MISTAKEN, because it is an outward statement that leaves space for others to exist, which is the FUNDAMENTAL PRINCIPAL of style. The long-sleeved, collarless, buttoned shirt under the sport coat is also, I think, a great way to create an INTERMEDIATE step from not wearing the collared shirt under the sport coat to wearing one under the sport coat. This is quite a step for those of us who are not used to wearing a collared shirt with the coat. My personal feeling on the matter of collared shirt with jacket is that it can concentrate too much of the attention, a major style faux-pas, especially if you are the ONLY ONE WEARING A JACKET in a specific social situation.