Standard tyre size on the 20vt wheel like Andy has got is 205/50R16.
Not the cheapest size in the world for tyres I can assure you from personal experience. I'm having 2x Goodyear Eagle F1s fitted to mine (front) and lets just say its costing a small fortune.
Longest Serving BOO Member
Stilo (3dr): Mar 06 1.4 16V Active Sport / 28,500 miles
Coupe: Feb 97 20V N/A / 136,000 miles