Just as there are lots of different ways to get stitches on the needles for toe-up socks, there are lots of ways to finish a sock, too. The only consideration needs to be that the bind off is stretchy enough for the sock to get onto your foot, but of course not so stretchy that it won't hold to your leg while you're wearing it!
One of my favorite stretchy bind offs -- again because it's easy -- is known as Peggy's Stretchy Bind Off. This bind off requires a set up round in which you add stitches that are then slipped in the bind off round, adding a little bit of extra yarn to the mix that does, indeed, make a stretchy bind off.
You can also try the knit through the back loop method that Eileen Casey introduced us to, among others.
If you have a favorite bind off for toe-up socks or other projects that need a lot of stretch, I'd love to hear about it!