depends. The first thing I would do is to make sure your monitor is calibrated, as your major complaint is that your prints come out too dark.
I won't say that it's necessarily better to add a +1 EC all the time, but for the most part, I think I and many others leave the EC dialed up by anything from +1/3 to +2/3.
It depends on exposure mode, scene, type of lighting, the look you're desiring, and ISO used.
The 7D exposure meter and the evaluative AE is really good, and prioritises the AF point chosen.
I'd say, try out different exposure modes, and various EC settings, and see what you get. In the meantime, if you don't already do it, look at the histogram to determine brightness, not the LCD preview.
Thanks. So, would shooting at a +1 Exposure Compensation help in general?