I heavily endorse the following lines for my rods: Phoenix silk lines, Terenzio silk lines, Cortland Classic Syllk DT, Cortland Classic 444 DT, and SA XPS DT Lines. These are fairly well tested, well liked, and used commonly for bamboo rods currently. As far as silk lines go they are very expensive but they exemplify some of the best attributes and properties that complement a classic bamboo rods action.
Above from left to right: SA XPS DT, Terenzio Silk Lines, Cortland Peach 444 DT, Phoenix Parallel Lines, Phoenix Silk Lines, and Cortland 444 Classic Sylk Lines
If you are worried that the maintenance of silk lines is too much to deal with, don't, they last a very long time. After using silk lines wipe them down with a small square of chamois or soft t-shirt cloth (carry a 4"x4" square in your vest), and apply mucilin. If I fish it for five hours or more, I simply wipe it down for two minutes, apply mucilin and start fishing again, no big deal. I treat my “plastic lines” exactly the same way so the ritual is no different when it comes to cleaning and conditioning on or off the river. Don't feel like you have to baby silk lines, they are meant to fish hard and long.