Ah, y'see, I love the spelling Kaylee, although I know PPs have labelled it chavvy - it's the name of my favourite character from the short-lived cult tv show Firefly. I'd use it on that basis, although it probably wouldn't be top of my list.
I also think the Kayleigh spelling is lovely, and if you like it you should use it. If you're not sure, then maybe do something I think I've read on here before - write it, along with middle and last name, on a post it and leave it somewhere you'll see it regularly. Then you'll find out if it grows on you or not.