Whoa, this is an impossible question. Why? When you approach a new customer the first thing you do is sit down and design some basic dashboards with them. This will be based on requirements and needs of the business, along with use cases.
I have no idea what data you are representing, what the impact is on other services, what I am comparing this against.... you can't ask questions here about how best to represent your data. Thats really down to you to design, show to your users and ask them. If they want improvements they will help you drive them, plus you may want to do some basic statistics.
My closing points, have you tried a line, stacked or other chart? Just try them all and see which ones best represent the data. I quite often find that a single chart ends up better when split into two and perhaps pulldowns added to make it a little more interactive.
