Depends on what your definition of a top quality striker is I suppose. Here's the strikers for the last 13 league winners. I'd say it's usually 2 top quality strikers, and then a 3rd striker or pair of strikers who can help pick up another 10 - 15 or so goals.
However, there's hardly a trend in that either. Chelsea and Arsenal clearly do it differently, relying a lot on their midfielders to pull in the goals rather than their 2nd or 3rd strikers.
2013/14 - Man City : Agüero (17), Dzeko (16), Negredo (9), Joventic (3)
2012/13 - Man United: Van Persie (26), Rooney (12), Hernández (10)
2011/12 - Man City : Agüero (23), Dzeko (14), Balotelli (13), Tevez (4)
2010/11 - Man United: Berbatov (20), Hernández (13), Rooney (11)
2009/10 - Chelsea : Drogba (29), Anelka (11), Kalou (5)
2008/09 - Man United: Ronaldo (18), Rooney (12), Berbatov (9), Tevez (5)
2007/08 - Man United: Ronaldo (31), Tevez (14), Rooney (12), Saha (5)
2006/07 - Man United: Ronaldo (17), Rooney (14), Saha (8), Solskjaer (7)
2005/06 - Chelsea : Drogba (12), Crespo (10), Gudjohnsen (2)
2004/05 - Chelsea : Gudjohnsen (12), Drogba (10), Kezman (4)
2003/04 - Arsenal : Henry (30), Bergkamp (4), Wiltord (3)
2002/03 - Man United: Van Niistelrooy (25), Solskjaer (9), Forlan (6)
2001/02 - Arsenal : Henry (24), Wiltord (10), Bergkamp (9)