When Red and I installed my new kitchen shelving this past September, ( http://my1929tudor.blogspot.com/2010/09/ahhhh-dining-room-table-is-back.html ) I purchased a Ryobi laser level. It was a small hand held model, self levelling, that could be mounted on a tripod or adhered with a suction cup to a vertical surface, and it sold for $49. It worked like a champ -- I was very pleased.
I was pleased, that is, until I took it out for my living room cedar picket project. The suction portion worked, but the red laser was a no go. We tried new batteries, but alas, dead. A trip to Home Depot got me a speedy refund, and I purchased a different type of lasel level:
I liked the Ryobi model better, but obviously it needed to work for a longer period of time than it did. I guess the real test will come when I pull it out for the next project...!