Here are a couple of my Exclude filter expressions:

TV-XVID
Code:
/(\.|\-|[ ])(DVDR|DVDRip|Pack|Complete|Custom|Hebsub|Bluray|Cam|1080p|720p|internal|Subs|TS)(\.|\-|[ ])/i

XVID
Code:
/(\.|[ ])(R5|Line|TS|Telesync|Screener|WP|Workprint|Cam|Custom|HebSub|720p|1080p|480p|R3|19*|200[0-9]|2010)(\.|\-|[ ])/i

And an example of a single snatch filter
Code:
/^Castle.2009.*.720p/i

or multiple snatches
Code:
/^(Castle.2009|Weeds.S07E*|The.Office.S08E*|Tosh.0.S03E*).*.720p/i