Manfrotto LBAG110. Nice and sturdy with a broad strap so it doesn’t dig into your shoulder. Ample room for a stand, several even, with lots of accessories. The zipper goes down pretty far, so that you can reach smaller stuff in the bottom easily, but not so far down that those things fall out. I have trudged many, many miles with this bag...
They have a smaller version as well, if you use a smaller stand.