Richco WHC series nylon cable clamps are the best solution for all wire and cable management needs. They are much better than cable ties because cables are held firmly in place, but can be easily inserted and removed as configurations change. No cutting of cable ties is required.
I have been using them since the mid 1980s to manage cables in 19″ equipment racks. They mount to any surface using a #8 or #10 screw. The WHC-1000-01 (with a 1″ diameter) is excellent for managing cables under the computer desk and at the back of home entertainment systems. I screw several to the underside of computer desktops along the back edge at 1′ intervals to hold cables up and out of the way.
The slightly smaller WHC-500-01 (1/2″ diameter) is excellent for holding rope lighting in place. The mounting hole can be tapped with 1/4-20 thread screws to hold a small flashlight such as the previously reviewed Fenix LD01 to a small camera tripod mount. I have also mounted several to 3/4″ rare earth magnets to temporarily run cables along a T-bar ceiling. Another trick is to bolt two 1″ clamps together to form a figure 8 and you can then use it to manage cables on a wire shelving unit.
The uses are endless and the price is right.