I find it strange that so many people find the Madonna song so bad. Why is that exactly?
I actually think it's a really nice and fitting bond theme. It is very up-tempo and energetic, which bond films allways are (car chases, fights, amazing stunts and so on), it has the same bombastic, imposing sound as old themes like
golden eye or
diamonds are forever, because of the use of strings
and it was the first Bond movie from the 21th century, which makes it kinda ok to give the song a rather modern/futuristic sound with the electronic elements.
When I hear the song I can perfectly imagine a trailer for a Bond movie that goes perfectly with it.
I guess it's the electronic elements that most people don't like about it. This kind of music isn't very popular in America, I guess. People in America even call this techno (which this song clearly isn't by European standards). And maybe - I'm getting on thin ice here

- it's also because people love to hate madonna (but I don't want to say everyone who hates this song necessarily hates madonna!!).
Now, about the new Bond theme: I don't really like it, because 1) it has a man voice and I prefer women's voices in 99% of songs released, 2) the strings aren't really that noticable, and the symphonic part of a bond song should be prominent and 3) the rest of the music seems a standard pop/rock song.

But maybe it will grow on me. I allready like it better after hearing it a few times.