NASCAR 08 seems to do an okay job in the grand scheme of things. The cars and tracks both look like they do in the real world. But there isn't really anything in the game's look that stands up and makes you take notice. There are a couple of visual effects that add to the game's overall quality (like the looming smoke columns after collisions), but they aren't really enough to make up for the general average feel of the game.
Sound is very underwhelming. The best thing about NASCAR is the sound of 46 high-powered engines thundering around the track at top speed - a feeling that is completely absent in NASCAR 08. The music selection is a nice mix, though I really wasn't feeling it at all. During races, your pit chief will feed you information, though his advice falls into the same category as the commentary on EA's sports titles; sometimes it makes sense, though you'll also hear a lot of useless trash.