Wow, I could not have thought of a more vague question as that. Thats like asking, "what is the best car?" You want to chime back and explain your query or is this just for sh!t and giggles?
Earl, the best 7.1 surround system that can come to my mind will cost you up near 750,000 dollars. Enjoy.lol
Really though, with a budget in mind, take a ride into your local, nearest hi-fi shop with you Dad on a Saturday. Have a listen to a few full system setup's, and buy, within budget one that sounds best to your ears. What might be best to me, may not be best to you. Only you can decide that. A lot of good sounding budget stuff out there these days, and its only getting better. Have fun and happy shopping.
Monitor Audio makes speakers that look more expensive than they cost and sound great too. They'd be a good HT choice. The Bronze or if you want something really nice, the Silvers. There are many other speakers out there however, that may sound better to you than the Monitor Audios. Examples - PSB, Paradigm, Mission, Tannoy, B&W, NHT, Mordaunt Short, Wharfedale, Focal, etc.
Receiver you'd be looking at NAD, Cambridge Audio, Rotel, or Arcam if you value good sound quality for music playback. Marantz, Denon, Yamaha, Onkyo, Harman/Kardon are a step down in SQ but they will probably land you more features. Lower still are the Sonys and JVCs of the world - most audiophiles would tell you not to bother with these mass market brands. And there may be higher end options than NAD/Arcam/Rotel/CA, but unfortunately I'm not aware of them.
Hopefully this gives you some direction in terms of starting your search. Reading reviews doesn't hurt either but the truth is that most reviews are very positive. All the brands listed here are quite well regarded, keeping in mind the part of the market each brand is competing in. And the higher up market you go the more accolades a component tends to receive. In short, these companies all make good product - the question is which provide the best value and what sound do you prefer? You need to listen to be sure.
A good way to find some dealers in your area is to go to some speaker company websites and search for retailers. All the pretty pictures of speakers are nice to look at too.
Good choice on the speakers, Dan, but I'll add this.
If the system is going to be used almost exclusively for HT (and not for critical 2 channel music listening), most of the mass market AVRs will actually be "good enough". I have a el cheapo Yamaha AVR on my secondary system (for XBOX and the kids mostly), but it does a really good job of HT.
Keep in mind though, if you pair this with crap speakers, it's going to sound just like that - crap.
Oh yeah, and in my opinion, don't bother with 7.1, 5.1 is good enough. In fact, the vast majority of movies out there are mixed in 5.1 anyway.
Hopefully Blu Ray will start popping up 7.1 movies and make the invesment worthwhile...for my 2 cents worth, a good mid price range Yamaha amp such as the 1800 and Mission or KEF speakers and you're on your way to a good system