I wasn't planning on taking 4 days off from running in a row. It was more a product of cold weather, busy work days, and treadmill freeze. However, when I started my run today, I immediately felt fresh and strong from the mini vacation. I ran an hour at a good 8:15/mile pace. 7.5 miles never felt so easy. It is a product of building my fitness the last few months and it shows you, rest days are good.
People often freak about not running for a couple days or having an injury/soreness keep them out for a week or two. The truth is, even up to 2 weeks or so without running, you will not see a drop in fitness. Actually, the rest of a few day to a week would probably increase your fitness through recovery.
That being said, I have been irritated by not being able to run for 4 days. That may be a product of our winter that won't F-ing end though!