heres a couple of awesome sites.
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=104x2617492#2617521
one of our growing number of amateur researchers put together a list of machines and how many people use them. Here is the info for Ohio as an example.
oh,"Danaher Controls (Danaher Guardian)",1088944
oh,"Diebold Election Systems",485824
oh,"Election Systems and Software, Inc. (ES&S)",5645336
oh,"Fidlar Doubleday",195209
oh,"MicroVote General Corporation",183077
oh,"Sequoia Voting Systems, Inc.",228878
oh,"Triad Governmental Systems, Inc.",3001526
oh,"Voting Technologies International",546773
oh,"unknown",60231
also so that you can know your machine better please see the following site
http://www.evoting-experts.com/
on the right hand side of the screen is a box called voting machine information