GameFAQs has descriptions next to its ratings for games, and I always agreed with what they describe as a certain score (out of 10).
I've always thought these words are pretty basic quality descriptions, nothing fancy like "awesome" vs. "amazing" (which one's really better?), and they're distanced enough from each other so that there's really no confusion in what you think the rating should be if you go by the descriptions.
I don't think 10 is too many choices. If I'm going to give something a rating, I want some room to distinguish it from things I don't think are quite at its level. For example, I think X is a 3.0, Y is a 3.5, and Z is a 4.0. These are very different rankings, because as it is, there will be things in the 3.0 ranking I like more than others in the same 3.0 ranking, but yet still less than anything in 3.5 - it's general but descriptive. But if we start to smush rankings into each other, now X and Y are in the same class, 3.0, and Z is way better than Y, 4.0. I like 1-10 ranking systems for this. Sure, we could have 1-20, 1-100, whatever, but 1-10 is pretty common and I think it works well.
I don't think abuse is something anybody should try too much to combat, because it's just going to exist no matter what. Some people rate things 5/5 before the album has even come out. And some people rate 5/5 if they "like" it, so a good 80-plus percent of their ratings are 5/5. That's okay, let them rate how they want, and the people who want to make meticulous use of it will. I think it will be like that regardless of any system used.
Wow... I need to get on it and give some more soundtracks ratings! And fix some of my old ones... they're from when I first joined and didn't really have enough sense of good ratings yet.
Datschge: Sometimes I can easily say "I like X soundtrack more than Y", and then that would work. But sometimes the soundtracks are too different, and I like them "equally" for different things (and I quote "equally" like that because it's too hard even to say that since they're so different, they can't really be compared). If X and Y are really different from each other, but both deserving of a 3.5, I wouldn't want to have to rank them against each other, but instead I'd want to give them a rating based on what they deserve for what they do (in my opinion of course).