What are the top ten bird books you find the best quality and/or most useful?

Lynx HBW (counting all this as one!)
Mullarney et al - Collins Bird Guide
Snow & Perrins - BWP Concise
Hagemeijer et al - EBCC Atlas of European Breeding Birds
Gibbons et al - New Breeding Atlas
Sibley - N American Bird Guide
Harrap & Quinn - Tits, Nuthatches & Treecreepers
Hayman Marchant & Prater - Shorebirds
Urquhart - Stonechats
Clement Harris & Davis - Finches & Sparrows