I am a Daniels guy, so what you will hear from me will be very similar to what you would read in Daniels' book.
When I am 5k training, I like a bit of speed work (200s/400s at mile race pace) early in a training cycle. I like a big block of vo2max work (longer intervals at 5k pace) right in the middle. Tempo efforts are incorporated throughout, usually once a week. I usually close out a training cycle with a combination of 200s/400s and race simulation workouts. A training cycle might be as long as 18 weeks, but can be as short as 10-12 weeks.
When marathon training, 200s/400s go out the window. I do one vo2max block early on (from 18 weeks out from the marathon through 13 weeks out), then it is all tempo, all the time. The point of that is to improve my anaerobic threshold so that I can run at a faster pace and stay aerobic - which is the key to the marathon. For elites, getting in some faster stuff during marathon training would still be important as they will want to be well positioned to throw in and respond to surges; but for age groupers shooting to run their best possible time with a steady and consistent effort, vo2max intervals late in a marathon cycle don't give you nearly as much bang for the buck as long tempo sessions.