"Eau de Cologne," "Eau de Toilette," and "Eau de Parfum" refer to the concentration of perfume oil in a given scent, not to the way it smells. Eau de Cologne (EdC)concentrations generally run about 3% - 5% or less, Eau de Toilette (EdT) fall roughly in the 5% - 15% range, and Eau de Parfum at 15% or 20% and higher. Even higher concentrations are typically labeled "Parfum Extract."
There are some serious complications to this system. First of all, the percent concentration boundaries are not firm and differ depending upon whom you ask. Often they'll be listed as overlapping ranges. More importatntly, the quality and potency of raw ingredients varies widely, so that some EdTs smell much stronger than other scents marketed as EdPs. For example, the EdT A*men smells much more potent than the EdP version of Boucheron's Jaipur Homme. You'll also find that many people (some of whom should know better,) refer to all male scents as "colognes," whether or not they're actually EdC concentration. I believe that most men's fragrances on the market today actually fall into th EdT concentration range.
Perfume oil concentration impacts longevity as well as potency, so that the EdP version of a given scent will usually outlast the EdC or EdT. Some scents are produced in multiple concentrations, and in many cases the concentrations smell different, not just stronger or weaker. Guerlain's Jicky is a classic example of this phenomenon. You'll find that many Basenoters have distinct preferences among the different concentrations of such scents.
There are hundreds, if not thousands of scents with "moderate sillage and long lasting power" on the market - so many that naming a specific brand is not going to do you much good. In any case, sillage and longevity can vary widely within a brand. When choosing a scent, concentration is much less important than how much you like the way it smells and how comfortable you are wearing it. If a scent you like is sold in multiple concentrations, you can try each and decide which suits you best. The trick is to test as many scants as possible (on your skin - cardboard stips are useless) until you find one you like. The reviews in the Basenotes directory can help you decide which fragrances might be the most appealing.
Hope that's a help!