Just got a 360, some questions

[Calve]

I finally got a 360 for Christmas, however it hasen't been all smooth sailing. I got the bundle which includes GRAW, however the game did not work. The system did not read the disc and only a few times I actually got the game, and when this happened it was filled with bugs. I initially thought it was the system however the arcade disc, original Xbox games and DVD's ran flawlessly.

I got NHL 07 yesterday and it worked well. However I'm some what paro and noticed that the frame rate wasen't the best (especially the opening EA sports animation), however I had read that this frame rate was synonomous with the game. Then came another scary moment. When I was playing an odd black line appeared in the middle of the ice for like 5 seconds until the play ended. The game continued on perfectly and has been flawless since then.

I've also noticed that 360 is a much louder system then original Xbox. I don't know if its just my system? Its not a sound that worries me because it simply sounds like its reading the disc, however it is very loud and is very noticeable... I don't know if this is a characteristic of 360 or just a problem with mine?

So my question is; should I exchange my current 360 for a new one? I'm wondering if I should just exchange GRAW or the entire system...

If anyone could help with any advice or insight on these occurences it would be GREATLY appreciated.

Thanks!