I Used Mountain Bike SPD's for a long time and they work well enough and great on the durability issue,
But I have for the last 10 months used the Time pedals and cleats and I would suggest looking into them.
Very easy to use and no covers needed. The have a built in wear indicater to let you know that the cleat needs replacement. If you can find the entry level no frills version they are not to expensive, but lack adjustment.. But like everything else the prices go up very fast.
As a side not they have recently added a new revamped version for 05.