I have three different access points in my house right now.. (2.4ghz b-g for old media players, etc.), (2.4 ghz G only for primary access from G devices), and (5.8 ghz N for those devices). The reason I use the 2.4 ghz G access point is because it is a pro grade Colubris (now owned by HP), and the signal strength is much better than any consumer product out there.
But all of my playback devices (3 PS/3, 3 WD-live, 2 Apple TV, and many other computers) are all pretty much wired. The only devices that are not using wired are the laptop we leave in the living room with a SSD drive so it boots up quickly, and various tablets and phones of course.
I get gigabit speeds on the wired connection. On wireless, on a good day I can get 17/18 mbps which is unacceptable for video streaming, etc.
I have a 24 port gigabit switch in my office with about 20 ports filled. There is also a 16 port gig switch under the main TV viewing area in the living room to supply ethernet to the 3 dish receivers, PS/3, Apple TV, WD-live, etc. there. There is also a 8 port gig switch in the theater which supplies ethernet to PS/3, HD-DVD, AppleTV, WD-live, computer for DVD inventory, etc. There are also two 8 port switches in the two girl's bedrooms. One daughter has 6 ethernet devices (4 computers, appleTV, PS/3), and the other has two computers, and the third WD-live feeds off of that switch.
It is not difficult to run ethernet cables, but you need to know what you are doing. As has been said before, if you have not been in an attic before, and do not know how to safely walk in the attic, leave it to an expert. Otherwise you might have to spend more money on ceiling repair.