Well, I've had Twilight Princess since the Wii launch, and have so far played for about 25 hours.  I am on the fifth temple, Snowpeak Ruins, about halfway through.

So far my favorite temple would have to be the Goron Mines, mainly because the Gorons are my favorite race in The Legend of Zelda series, and I liked the sub-boss and final boss (although the final boss was incredibly easy, as I didn't take any damage whatsoever.)

My favorite weapon so far is the Spinner, which is found in the fourth temple, Arbiter's Grounds.  It is a really fun gadget to use, and the boss that you fight using it is incredibly fun (although it is once again too easy).  The only problem is that I don't see how the Spinner will be used outside of Arbiter's Grounds.  The Clawshot on the other hand, is a very useful and versatile weapon that is once again found in the water temple.  It also has a cool new ability that allows you to lower yourself down on the chain.

The graphics are amazing, no matter what anybody says.  People will say that the level of detail is bad and the texturing sucks, but really, who cares?? 

The controls are also amazing, and definitely the best thing to happen to the series.

So anyway, buy this game, whether you have a GC or a Wii, as it is probably the best in the series.