I think that all of the important points have already been said, but there are two that I would like to reiterate:
1. The story of the first one, especially at the end, is *really* good. It's really exciting to have everything come to a head at this point, and... it's difficult to describe, but I'd say that the story at the end of ME1 was the best in the series, despite its lackluster gameplay.
2. ME1 was designed to get you immersed in the vibrant universe of Mass Effect as completely as possible. The other two were designed to carry on with the knowledge that you've accumulated, so you won't get as good an experience out of ME2 & 3 if you skip it. I'm sure that they would do a good job of getting you into it anyway, but you'd really be missing out.
1. The story of the first one, especially at the end, is *really* good. It's really exciting to have everything come to a head at this point, and... it's difficult to describe, but I'd say that the story at the end of ME1 was the best in the series, despite its lackluster gameplay.
2. ME1 was designed to get you immersed in the vibrant universe of Mass Effect as completely as possible. The other two were designed to carry on with the knowledge that you've accumulated, so you won't get as good an experience out of ME2 & 3 if you skip it. I'm sure that they would do a good job of getting you into it anyway, but you'd really be missing out.