Here's my long answer to you:
Mass Effect was one of the first next generation RPGs and quite a special one in it's gameplay alone. I believe that there are many types of RPGs: some with great stories and poor gameplay, some with poor story and great gameplay and some with a good balance between the two. Mass Effect has a good balance between gameplay, story and especially backstory.
Personally, I just like the whole storyline. I thought it reminded me a lot of Star Trek with all the different cultures, races, the Alliance (like the Federation for Earth), etc. That's one of the reasons why I thought that the story was going to be awesome because everything made sense. And because you learn all the backstory between the races, the action scenes get even more interesting. You know why you're Spectre, you know what are your implications, etc. We also get a great view of how the political affairs take place in the not-so-distant future! Even if there are not a bunch of battles, it sure gets intense whenever there's one!
With that said, we haven't seen a game as mature as this one before, especially set in a sci-fi world (which makes it even better in my book). Also, did you ever feel sad when finishing a good game (kind of like any Zelda game really)? Well, same thing happened to me for this game, and I'm sure I'm not the only one thinking the same thing. God, the ending was just too epic, especially when you have invested a couple of months in the game like I did. I always thought "Oh, this is how it all ends? Hmmm, ok..." but then another fight starts and another cutscene appears, etc. Let's just say I haven't been so proud to watch the credits of a game in my entire life (and the music was pretty good, it matched the style)! I was sad at the same time because I would have to wait years for a sequel... Luckily, ME2 comes out next year!
So that's my 2 cents.
Random game thought :
Why is Bionic Commando Rearmed 2 getting so much hate? We finally get a real game and they're not even satisfied... I'm starting to hate the gaming community so f****** much...







