depends on the compressor hump. if its only in the back corner, prolly 3 kegs like samc's setup.
if its a full hump from back to front, you'll fit 2 kegs max, unless you have a very tall collar that lets you put a 3rd keg on the hump.
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