OK, here is my own personal top 10 (if anyone cares!) starting with my favourite at 1:
1: Lennart Green's Laser/Snap Deal - hard to master, but will slay an audience. Must be performed sat down at a table, though.
2: Daryl's Ambitious Card - check the Daryl DVD/Video
3: The ID - all time classic, so easy!
4: Paperclipped by Jay Sankey - I've even fooled fellow magi with this one
5: Gary Freed's NFW - will make jaws drop
6: The Colour Monte - when I first performed this, I made a woman cry!
7: Torched and restored by Brent Braun - Easy, slick and impossible!
8: Presto Printo by Daryl - carry this one everywhere. Great bar trick. Instant reset.
9: Credit Card - my own invention... banknote is folded and becomes a signed selected card. Email me for the routine...
10: Regal's Special Delivery - signed card to envelope routine... awesome
ADDITION: between 2nd and 3rd place I would like to add Paul Harris's Deep Astonishment. Just got it, got the handling down in 10 minutes, performed it to some friends, they now think I'm Max Maven, but without the black triangle
Also, I recommend the books 'Art of Astonishment' by Harris. Certainly not for amateurs, though.