Put It All Together
Once your TV is mounted and your video sources are properly sorted out, it's time to connect everything. If you've done your homework on your peripherals, you have a list of HD and SD sources, and you know what cables you need to hook them up.
For all of your high-definition peripherals, you should be using HDMI cables--or perhaps DVI with an HDMI converter, in the case of older components. If you plan to keep some standard-definition sources, such as a standard DVD player or SD video camera, connect them via S-Video or component ports if possible. These are of higher quality than RCA, or composite, jacks, and your HDTV will up-convert them to its native resolution. Don't be suckered into buying a $100 HDMI cable at the store when you buy your television. It won't work any better than a $20 cable from a reputable company. Buy your cables online and save big. Remember, this is digital: You only need to move the bits reliably from one place to another--not give them back massages.
HDMI Musical Chairs
If you have more HDMI sources than you have HDMI ports on your new TV (which is quite likely), the simplest solution is to add an external HDMI switcher box. Such boxes are available from Gefen, Iogear, and OPPO, among other vendors, for about $100 to $200. Be sure to buy a box that has HMDI 1.3 ports, the latest standard. Some models switch automatically between active sources, and you don't have to bring an extra remote control into the picture. Plug always-on sources like your DVR and your cable box directly into your TV.
Another way to perform HDMI switching is with an audio/video (A/V) receiver. If you also need a receiver to power your new surround-sound speaker system, an A/V receiver may be a good choice. The inexpensive Onkyo TX-SR505 7.1 Channel Home Theater Receiver ($300) has two switched HDMI ports, as well as 75-watts-per-channel 7.1 surround sound. At the high end, the new 7.1-channel Marantz SR8002 THX Select2 Surround Receiver ($2100) comes with four switched HDMI ports, a built-in 480i/480p up-converter, and all the audio goodness you could wish for.