You want to buy an "Improved Neubaur" type. I believe they all have the exact same pattern. You won't need more than a couple of cover slips. The slips are very thin, but I've never broken one. You can see a picture of mine here, as well as a lot of other info and pics: http://www.homebrewtalk.com/f163/pics-yeast-under-my-new-scope-273342/#post3371061
. I bought it off ebay for about $30 I think.
There are better counters with brighter lines, and also with small wells that make adding your sample easier. At least this is what I've been told. I have had zero problem with mine.