I like the crisp sound of it, and anything that makes me think of Captain Kirk is a plus in my book, but I can't really work up any enthusiasm for Kirk. It might be Kirk Cameron, in all his banana-waving, gay-bashing, hyper-religious weirdness that taints it for me.
I guess I wouldn't mind seeing Kirk on someone else's kid, but it's not a name I'd ever consider myself. I agree that it's easy to pronounce and works well with Liam.