Single Colour Tyres / Coloured Tyres

Continental GP4000 have 2 versions of yellow, but at twice the price of the Zaffiro recommended above.

Schwalbe Blizzard Sport are available from Kiwi Cycles for about £11.

Schwalbe Lugano also available (many places) for similar money; but not very puncture proof.

Aren't Blizzard Sport and Lugano the same tyre, fairly sure they renamed the BS into Lugano...

http://www.wiggle.co.uk/p/cycle/7/Schwalbe_Blizzard~Lugano_Tyre_With_Puncture_Protection/5360031297/

(P.S. they aren't that puncture proof at all after about 6 weeks of riding.)