The more you run, the more you find yourself covering familiar territory, both figuratively (in your triumphs and tragedies, so to speak) and literally (in running the same distance many, many times). When you're in the 'burbs, and the streets are fewer and farther between, it's even harder to add variety.
Some people get bored running the same roads over and over, but I find it helpful. I can use landmarks to easily identify mile markers, and, more importantly, I can just put on my shoes and head out the door without thinking about it too much. (This is especially true when I run at night - it means I know the sidewalks well and can point my headlamp at oncoming traffic instead.)
These are the routes I run most often:
3.1 miles. Since this is arguably the most popular race distance, it makes sense to have a 5K route around your neighborhood. Whether you're a beginner or a veteran, you'll need to get used to this distance. One tip: Run it forward one day and backward the next to avoid injury and boredom.
5 miles. This is another popular race distance. It's also a good test of how well you're progressing beyond the 5K. When you start speed work, this will make for a good fartlek or a quick tempo distance, too.
7-8 miles. I have a 7.6-mile route that I do often. This distance stands at the edge of my fatigue threshold, meaning it's as far as I can run on an empty stomach. Anything more and I need some pre-run fuel. It's a good "test" for me, to see how well training has progressed.
10 miles. This distance isn't for everyone. It may take others quite some time to get here. But there's definitely something to be said for hitting double-digit mileage. The sense of accomplishment never dissipates. Just don't make this an out-and-back route that passes several pizza places in a five-mile span. You'll just get hungry. Trust me. Seriously.
(I don't have routine routes for longer runs. One reason is that I've realized my old reliable routes aren't terribly safe -- they lack shoulders and streetlights, neither of which are conducive to safe nighttime running. Another is the fact that I tend to overanalyze my runs; by mapping them out the day that I do them, I avoid this problem.)
It helps to have short loops you can add to these familiar routes. By hitting side streets, I can add 0.4 or 0.6 miles to my first two routes and another full mile to the last two. This works well if I need an extended warmup or cool down or want to make an easy run a bit longer. It also breaks up the monotony.
What are the ol' standby running routes and distances that you use? How do you keep them from getting boring?