Great from start to finish, which is definately not long enough!
Story: Its only fitting that with an RPG, I start with the story. First off, this game is fully voice acted. You will never be required to read wall after wall of text to take in the full story. That alone should instantly sell you on this game. However, if it doesnt, then I should tell that this game is WELL voice acted. Meaning you wont get any "jill sandwich" worthy lines in this title (and if you dont get that reference, then go buy the original resident evil and play it). The story also has several twists and turns which keeps it pretty interesting. Even better, you can effect the story with your "paragon" or "renegade" choices. Each one is worth experiencing, which adds replay to the game, but we'll get to that later. All you need to know, is that the story in Mass Effect is good enough that you may play it again just to experience the twists and turns all over again.
Gameplay: The gameplay in Mass Effect is pretty damn good, but it isnt without faults. The combat in the game plays like a first person shooter...with powers. You have a varied selection of guns at your disposal, based on your class choice. The classes in this game are well-balanced. Each one plays differently, and will require you to alter your strategy. If you play an Adept like a Soldier, you will die a lot. So you can choose different classes based on your preference, and thats a nice touch. There is also some great customizable options in the game. You have several fields (and when I say several I dont just mean three or four, I mean like 7) which you can improve that will make that field stronger. They range from Pistol skill to specific Biotic powers, to specialized class advancement. How you spec your character will have a direct effect on how effective your character is in combat, so make wise choices. Your team mates will also be able to grow, and you can either set them to "auto-level up" or manual, based on if you want to fuss with them or not.
However, like I said the game isnt without faults. In the 360 version of the game, the cover system doesnt always work as well as you might think, and you will be left running blindlly into cover, only to find that you wont grapple with it quickly. Furthermore, the sprint function is easy to screw up, since you run so fast and uncontrollably, that you will probably overshoot the cover, or enemy, that you were trying to approach. The vehicle you use to traverse planets can also be a little unruly as well. The squad commands on the 360 version are also not great, since you can only give general blanket commands to your team, leaving little room for tactical placement. Notice that the afforementioned faults are with the 360 version, as the PC version fixes most of these. On a final note, the hacking game on the PC is a little better in my opinion.
Graphics: The graphics on this game are pretty damn good, considering the scope of the world you are playing in. There are numerous planets, lots of missions, tons of characters and the graphics dont suffer because of it. I am honestly surprised that this game could fit on one 360 disk. The game will suffer some graphical slowdowns and framerate issues during larger firefights and, for some reason, elevator rides. However, the game still looks great, and the great look will help to immerse you even further.
Overall: Mass Effect is just a great RPG. It has a heartfelt and touching story, with many twists and turns, as well as heart-pounding combat, some challenging (and at times, aggravating) boss battles, and LOADS of replayability. If you dont play this game again just for the story, you may well do it for the achievements, to try a new class, or be a paragon or renegade, depending on which way you went in your first play through. All in all, its hard to find a better deal, especially since nowadays, you can find a used copy for 30 bucks.