Wow, a tough question indeed!
I've got a top 4:
Paul Oakenfold, John Digweed, Nick Warren, and Steve Helstrip.
They all have dropped some really fat sets over the years and are masters of the craft in their own right.
There are really quite alot of good DJs out there now.
Jon O'Bir has also put out some great sets, many free for download off his site;
www.jonobir.com.
Cheers!
-Alex