First off, there's a lot of good info
here. Secondly, glad to hear you went with Dish's HD package!!
Now.. down to the fun stuff.
1. Receiver: get something good. Don't even piss around with the Sony's, JVC's, Pioneers, and the like. Head straight for the Yamaha, Denon, Integra, or Marantz. These receivers give true power ratings from 20-20k. Crappy receivers rate their power at 1k with only 1 channel driven. This is not "real world" power. Well, unless you listen to 1k sine waves from only one speaker all day.... Put in some dynamic material and try to drive all 5 speakers in a home theater setup, and the power out of crappy receivers is usually cut in half.
2. Subwoofer: First, address whether you want it loud as fuck or sonically accurate. Most of the time people just want it loud as fuck. Sometimes both can be had, but it is usually expensive to do so. A few good examples of subs that can do both would be the Klipsch RSW-15 (this thing is a fuckin beast), Definitive SuperCube, or Paradigm Servo 15. These are all extremely accurate subs, and have the capability to be quite loud if asked to do so.
3. Center channel: This is where you should go a bit overboard. It handles about 70% of the total soundtrack. I have found that the first 2 things a person wants to upgrade in his home theater is a better center channel and a bigger sub. Look for something with a solid cabinet, a knock on it should give a "dead" sound. Definitive makes a series of powered center channels that are fucking amazing.
4. Front satellites/bookshelf: This could depend on the music duties that the system will also perform. If you are going to be doing a lot of music listening on your system, then go for a nice set of floorstanders. If you will be doing mostly home theater, your sub will be bringing up the low end, therefore you can get by with a set of satellites or bookshelves here. I am an aspiring audio purist, so I don't like the idea of relying on a sub to bring up my low end, so I have a very nice set of floorstanders with transmission line enclosures (hell yeah, baby!).
5. Rears: this is where you can skimp a bit, if you feel the need or desire to. These will be handling mostly ambient effects, bullets flying by, rainwater, and such.
6. Other: you could add another set of rear speakers and use them as surround back in a 7.1 setup
AND STAY THE FUCK AWAY FROM ANYTHING BOSE!!!