We tried an assortment of markers in our first semester (Spring 2007). Thanks to our Student Computing Labs Manager, we found the perfect markers and erasers. Perfect, in that both are magnetic. The markers include teeny erasers on the cap. While the markers are expensive, they seem to last pretty well and we keep the eraser caps as spares once the markers are spent. The erasers are a simple ergonomic design and are surprisingly inexpensive. Plus they have the added bonus of looking like mice. How cute.
TUL Dry Erase Markers, 12 pack
Office Max Brand Magnetic Marker Board Erasers