Don't let anybody kid you - your best answer above suggests a doubt about the effects of electrical interference. WOW.
I have been involved with electronics and acknowledged as expert repeatedly by others since 1972.
Electrical interference is a VERY REAL problem
Make no mistake, the handling, bending and even tying down of Ethernet cables without due care can all introduce inefficiencies and/or disruptions in the performance of any network. Even if your network seems to be working ok - is it really? I assure you - if you violate certain considerations - your network performance WILL SUFFER.
My experience suggests that electrical interference introduced by a wide array of potential culprits is by far the most deleterious bane of many network messes I have had to sort out over the years.
My rule of thumb is to buy yourself a good one ft. separation between any AC line and any parallel run of unshielded Ethernet cable. In moderately noisy locations - you may get away with 6 inches - I would never run any closer. You should also avoid crossing an AC cable at a right angle within a few inches if, possible.
I have seen people do such stupid things as resting transformers directly on patch cables... and then swearing off their ISP or computer tech.
Stop and think what you are asking the technology to do - or do you not know - and you'll quickly understand why it is in your best interest to do everything possible to avoid causing issues if you want to get the performance you're paying for with your equipment investments. Not paying respects to the care of network cabling and its installation is anathema to plugging your system unit into a surge suppression or UPS device that isn't grounded on the other side - you're just shooting yourself in the foot while pretending you haven't.
Never buy the argument that someone else did something and it didn't affect them. It's almost always provably wrong. Let me recount the number of people who failed to heed advice regarding the electrical protection of their systems - and the actual ground quality of their outlets.... oh - I don't have that many spare years for the typing.
If you are installing this stuff yourself I would STRONGLY advise tou to further research and ensure you have the specifications for terminating Ethernet cables properly AND FOLLOW THEM TO A 'T'! If you doubt at all, the quality of termination you have just made - redo it - it isn't worth later frustration. Make sure you do not sharply bend your cables at any point (the published standard is a minimum bend radius of 4x the diameter of the cable for UTP and 8x for STP.) also - do not pull with excessive force or jerk the cable to get it through or by some obstruction while pulling.
The only physical difference between 10MbS (older cable) and Cat5e is the amount of twist on each pair and the pairs among themselves within the jacket of the cable - THEREFORE - you are kidding yourself if you think distorting the shape of the cable by insensitivity during install can't come back to bite you later.
Pay attention to detail and you will find yourself well pleased in the end. Otherwise you may still get things to work - but you may not be getting the speed you think you are. I should note - there is no Broadband service in the states yet that will challenge even a 100Mbs system - but you'll pay if you have to do many large file transfers between units on the network.