They sell a coating made just for garage floors that works awesome, There are kits like this one:
http://www.homedepot.com/webapp/wcs/...7&marketID=101
Or they sell just the coating itself at home depot, Or like bumper 2 bumper, etc..
This stuff works the best IMO, Tiles will crack and chip. The kits they sell come with a degreaser / cleaner that you can just put in your pressure washer tank and blast away. Or you can buy them separately as well.
If you want durability and a semi good looking garage floor this is the way i would go.
-Stephan