You've probably heard more about Castlevania: SOTN, than you have played it, and if so, you're missing out.
Gameplay 9/10
Let's start with what, at heart, makes this game timeless, it's gameplay. SOTN's gameplay is absolutely amazing. With hundreds of different weapons, shields, and armors, and way too many zombies to kill, you'll never get tired of finding that new sword, and using it kill and ridiculous boss. And let's get this straight, the bosses are ridiculous. From rival vampires, to a massive ball of dead corpses, the bosses never cease to thrill and amaze, and offer a consistent, but never frustrating experience. The only trouble I have with the gameplay is the 360 controller itself, since it'll take a little getting used to, to play a 2D platformer with a joystick. Since we are all aware that the D-pad on the 360 is pretty much a joke.
Graphics 9/10
The graphics still hold up to the basic standards set by portables, save some 3D effects used in the backgrounds, which are showing their age. It should be noted that the graphics have seen somewhat of an update, and they have be stretched to widescreen, solidifying this game's 9/10 rating.
Sound 9/10
The soundtrack in this game is timeless, and you'll find yourself visiting certain area's of Dracula's Castle just to listen to the music. The sound is also very well done and appropriate, although somewhat metallic sounding.
Trust me when I say that this game will last you a long, long time, and you'll enjoy every minute of it. It's a great way to dive into XBLA, and an absolute must if you happened to have 800 points lying around. SOTN's rerelease on XBLA, above all else, will finally allow you to get a warm fuzzy feeling every time you see it on an "All Time Greats" list, which is a reward in and of itself.