Having just posted my top 10 (with wiggle room) on 4MA - I thought I'd repeat it here. Mind you, it's a thankless task having to pick an arbitrary number out of all the great books I've been lucky enough to read this year....
Naming the Bones, Louise WelshThe Diggers Rest Hotel, Geoffrey McGeachin (Aust)In the Dark, Mark BillinghamGunshot Road, Adrian Hyland (Aust) Harbour, John Ajvide LindqvistHypothermia, Arnaldur IndridasonWatch the World Burn, Leah Giarratano (Aust)Cut & Run, Alix Bosco (NZ)Dark Blood, Stuart MacBride (UK)The Anniversary Man, RJ Ellory
If I'd had headcount I would have added:
Thrill City, Leigh RedheadA Few Right Thinking Men, Sulari GentillWhere Have you Been? Wendy JamesThe Old School, P.M. NewtonLet the Dead Lie, Malla NunnTrick of the Dark, Val McDermidMadigan Mine, Kirstyn McDermottGolden Relic, Lindy CameronThe Half-Child, Angela Savage
But as I said - it's a thankless task and there were lots of fantastic books in 2010.