You ABSOLUTELY have to check out Boyce Avenue !!!! They do the most amazing acoustic covers, like ever! NO kidding. I am really thinking about 1 or 2 of the covers as my first dance for my wedding :)
here are some of my favorites of theirs.
http://www.youtube.com/watch?v=6I3kgbBp6PY
http://www.youtube.com/watch?v=HzC2-GJu1Q8&feature=relmfu
http://www.youtube.com/watch?v=yAUMU3QQE6w&feature=BFa&list=SP0BD69368AB943C89&lf=list_related
http://www.youtube.com/watch?v=6XXRlQ8UVyo&feature=BFa&list=SP0BD69368AB943C89&lf=list_related
