Airgas.... but they were ridiculously expensive for a 5lb tank.. also they don't fill they swap, they have a bunch of locations though so they are convinient.
Nobby Bev in Plainville, CT does refills, not sure of price yet; but now that I have a 20lb aluminum tank that is pretty I'll be going there so I can keep my pretty tank :-)
Fermenting: Apfelwein x2
On Tap: apfelwein, coffee porter, IPA, Very Pale Ale
Up Next: fix/replace the keezer
"There's only so much wine you can drink in one life, but it will never be enough to save you from the bottom of your glass" - The Handsome Family