So a filtered index reduces the number of columns and (importantly) the number of rows you need to search, whereas an indexed view... does pretty much the same thing. Where would you use one over the other? We have not moved to SQL 2008 yet but we've had great success under certain conditions, putting an indexed view over a given table. The sorts of things we look out for are the need to regularly query a small stable subset of the table using an uncomplicated where clause.