It won't surprise anyone familiar with either my writing or my blog that Jack Vance had the biggest impact on me, and The Dog of the North probably owes more to Lyonesse than any other single book. I've already written about Lyonesse at length so I'm going address a different kind of influence here: not emulation but reaction. By this measure, the book I'm most indebted to is The Lord of the Rings, a wonderful book which now sets my teeth on edge. The Dog of the North is made up of half wanting to be Vance and half wanting not to be Tolkien.
This is a statement which needs qualification. All fantasy writers are indebted to The Lord of the Rings as the book which made a clear--and commercial--genre out of fantasy. Sadly many fantasy writers have repaid that debt by rewriting, sometimes repeatedly, the book which so inspired them. (In this they do Tolkien no favours, but that's a different story). There is no doubt that what The Lord of the Rings does, it does very well. If you want truly epic narrative, a richly detailed world, "Good" versus "Evil", you're probably not going to do much better. For the first ten or so times I read the book, that was enough for me.
Even Tolkien's staunchest defender would concede that The Lord of the Rings is nonetheless deficient in certain areas. The monstrous trilogy is a humour-free zone, female characterisation is perfunctory and the males scarcely more nuanced. The epic tone, too, can be wearing after 1,000 pages. Some feel Tolkien's work to be philosophically problematic--Christian apologetics generally don't wear well and he is perhaps tarnished by association with CS Lewis--but my real problems with the book are entirely artistic.
A lot of modern fantasy has been written in reaction to Tolkien: G.R.R. Martin, Joe Abercrombie and China Mieville have all in their way reinvented a grittier kind of fantasy. In The Dog of the North, Beauceron is a direct response to the anodyne fantasy hero in line of succession from Aragorn, while all the main female characters are there to fill a gap I found in Tolkien.
Negative influences, it seems, are as strong as positive ones.