html has some good points.
some yeast strains are 'less specific'. others are very attuned to a style. Like hefeweizen yeast...its not very flocculent, and easily produces esters and phenols to provide the cloves and bananas one expects in a hefe.
if you used a non-hefe strain...well then you won't have a german hefe on your hands...it might by a crystalweizen, or an american wheat.
it just depends.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10