Callum

[wareagle1217]

I really like Callum -- it used to be my #1 boy name, but I scratched it from my list because both my maiden name (which was Miller, actually!) and my married name start with M, and I thought it was just too much "M" sound. Same thing with Liam, unfortunately.

Stellan and Devon are both nice with Miller.

Other ideas that come to mind:
Kieran
Declan
Evan
Lucas
Owen
Cavan
Bretton
Landon

Cullen is another possibility that sounds nice with Miller, though there is the major "Twilight" association with it.

I really like Callum, but I don't think it flows well with Miller. I really like Kieran and Declan.

[mischa]

Callum does blend into your surname Miller and both have a double "l" so I don't think it's the best pairing. Declan Miller has a better flow. There is an Irish name Colm which is pronounced "Kuhl-uhm" that could be another alternative in regards to look and spelling. Here are some Celtic/Irish/Scottish or Welsh name ending in "n" or another letter...
Colin Miller
Alpin Miller
Gavin Miller
Ian Miller
Lachlan Miller (oh, I like this combo!)
Stuart Miller
Rowan Miller
Lorcan Miller
Tiernan Miller
Quinlan Miller
Riordan Miller
Aidan Miller
Brendan Miller
Eamonn Miller
Finnegan Miller
Ronan Miller