how important is weekly mileage for marathon training?

There have been a lot of great suggestions so far - most that I agree with. To sum it all up, when training for a marathon, key factors include:

1. Consistancy (consistantly running 45 miles a week will be MUCH MORE BENEFICIAL in comparison to running 65 then 15).

2. Long Runs (get them up, the more comfortable you are with running up to 20 miles - not just mileage, but TIME, the more comfortable you'll be in your marathon. Remember, you're racing for 3+ hours, if the furthest in time you've run before the marathon isn't even 90 minutes, the marathon WILL be tough! The long run is maybe alittle more mental then it is physical - you get your mind and body used to the idea of running for extended periods of time. I enjoy a good casual 20-22 miler, because it'll take me two and a half hours to do it - about my race time). This is why it's importantto not only get "marathon pace" runs in, but simply long runs at a more casual pace - because the overall time will be much longer. The marathon is about enduring, short faster runs aren't exactly beneficial) - (I knew a guy who would run sub 6 minute pace for training and bounce between 40-90 miles a week - never consistantly - he hit the wall at mile 16 of his marathon, around 95 minutes, right around the length of his longest time run).

3. Marathon Pace Workouts (aka MP/TEMPOs etc). The more comfortable you are with your pace, the better. Getting in "tempo runs" ranging from 5-12 miles would be insanely beneficial. The longer you can hold the pace the better.

* Something that worked for me was alternating my long runs. On a two week cycle - one weekend you run your long run (example: 20 miles), whatever pace is comfortable. The goal being you're running a long TIME (key on TIME - example: 20 miles @ 7min pace = 2hr 20min. The next weekend you do a MP (tempo) workout WITHIN your long run. Example: run 10-15 miles easy (similar to the long run the week before), though the final 10-5 miles you go marathon pace. This workout was the key to my marathon.

Quite simply, the more mileage, the more prepared you'll be. though not everyone has the time to run 100 mile weeks, so you have to compensate here and there. Though if anything, i'd make sure that you attempt the above 3 key factors.

Thanks for the input everybody....

Looks like I need to try to up my mileage!

It would take a serious lifestyle change on my part to get my butt out of bed in the AM to do doubles. So I will concentrate on getting a few extra miles in on the cooldown on the hard days, and stick with the one day off a week.

I have been starting to do marathon paced runs on my own on the saturday runs, and pickups to marathon pace on the long sunday runs.

My group likes to race all the distances, I think that's why we train the way we do. I used to be a 5k queen back in the day when the legs were younger. I cringe at the thought of them now! I just wish there were more local half marathons!