My three best are;

#REGEX#:vW{0,2}[i1]W{0,2}[a@]W{0,2}gW{0,2}rW{0,2}[a@]

#REGEX#:/(remove(me|)|unsub(scribe|)).(w{3})

#REGEX#:(?i)http://[.w_-]{2,20}@(d{1,3}.d{1,3}.d{1,3}.d{1,3}|[0-9a-f]{10,}.[w_-]{3,}.w{2}|[w_-]{2,10}.[w_-]{4,20}.w{2})

The first matches different ways of saying viagra; the second matches various unsubscribe links in emails; and the third matches a particular type of link that I see in a lot of spam messages from. 

Does anyone have others that work well?