I'm not going to touch on the SecuROM issues. That's been well covered by other posters - if you can get it without SecuROM (e.g. through Steam), do so. However you get it (legally), get this game.
The first in an expected trilogy of games from Bioware, Mass Effect is nothing short of exceptional. It is probably the first RPG I've played where I immediately wanted to create a new character just to see how my choices in the first playthrough might have gone differently. This game is extremely deep, contains a great deal of non-linear play, and has incredible replay value.
To give that a little context, I have quite a few classic great games that every so often I'll pull out and replay, that never really get old. Mass Effect left me not wanting to wait.
First, sound: virtually all dialogue is voice-acted, with some big names providing a professional touch to an incredibly immersive experience. There's a fair amount of background sound & dialogue, some of which can be quite humourous. The music is well done and has its own unique touch about it, something that is increasingly hard to do with so many sci-fi games & movies.
Graphically, the game is a joy to behold. You may have to play with some settings to get it quite right (shadows by default for example can display incorrectly on some people's machines) but as a general rule, the visuals are most impressive. One aspect worth mentioning is that the graphics aren't super-realistic, and this more stylised approach actually made the places and people seem more real to me.
The real beauty of the game is in the gameplay and depth. There are countless choices to be made about how you progress through the game, from character creation onwards. As is inevitable with RPGs, there is a certain bias towards the 'good' and the 'jerk' approaches, but there are some genuine 'shades of grey' decisions to be made, and some that actually felt like tough calls to make. The free downloadable content adds to this further. Dialogue is innovatively managed and there are almost always multiple ways to handle any situation. For me, one of the signs of a great story-telling game is where you respond emotively to a game, where you start to care even a little bit about the story, the characters, and your impact on them. Mass Effect definitely achieves this.
Whilst a few aspects of the gameplay in the middle portions of the game can get a tad repetitive (something Bioware acknowledged when starting work on Mass Effect 2), overall the experience is of a developing storyline within a vast galaxy, and the hundreds of little hints and details dropped throughout it make up for the occasional planet or building looking nigh-on identical. Combat is varied, fast-paced, but doesn't really degenerate into a first-person shooter, with assistance to aiming and the ability to pause, should the player so desire. Given the nature of the varied classes in character creation, you'll have to play at least twice just to properly experience all the different potential combat options.
In summary, get this game, if only to have experienced it. In slightly longer summary, Mass Effect is an investment well worth making. It's a game that delivers a superb story, excellent replay value, good gameplay, and by all accounts is merely the start of a three part series where you will pick up where you left off previously. That innovative approach to gaming is by itself worthy of applause.