I bought the Olive sandals in 10M for size 9.5W feet.  I am a picky shopper, and I live in Manhattan, so I really have to pay attention to my footwear.

These flip-flops are awesome.  When I moved to NYC, I needed a pair of light, thicker-soled sandals that would stand up to a lot of walking, but would still be cute and match a decent portion of my wardrobe.  Enter the Teva Mandalyn Wedges.  I love mine!  They are very comfortable, provide plenty of support, and allow for a lot of walking and standing without tiring your feet.  I can wear them all day, day after day, and they don't seem to wear down (there's a light imprint of my toes, but only barely noticeable).  Bonus, I ordered the 10M size for my 9.5W feet, and they fit just fine - no toes hanging off the edge, not too much extra room at the front or back end.  An excellent purchase, and definitely one I'll repeat when I need another pair.

Note: I wore them to a pool in a hotel, and they did slip a little on the wet tile.  Not a big deal, since most people would be careful on wet tile regardless; just thought I'd mention it.