Getting confused

Yesterday was in training terms a hard day (intervals) so today was an easy day. This is where my confusion starts. According to the more recent training schedules I've seen easy days are at an easy or slow pace, whereas some schedules prepared for the London Marathon count steady runs ( i.e. marathon pace ) as easy days. Which one to believe? I've heard mumblings on the Runners World forums that current schedules are too easy and don't really prepare you for the stresses and strains of running a marathon well rather than to just complete it. I suppose the best maxim I've heard is "Listen to your body". My body wasn't complaining and felt like it wanted to do something a bit quicker but not to quick so I plumped for the steady run this morning. I was glad I did, last weeks steady run was off the needed pace by 15 sec/mile but todays was actually under the pace by 8 secs/mile. The route was the same with a small corner cut off because I only wanted to do 6 (ended up doing 6.7)
I learned another valuable lesson today, my pace is all over the place but mostly too quick. I'm fooling myself into thinking I'm going too slow and speeding up and therefore exhausting myself before I should. This is where my Garmin comes into play. It tells me how fast I'm going and gives me the confidence to slow down but still reach my pace. Isn't technology wonderful.