Gen my question to you is are you buying for the "now" or for the future?
If you're buying for the now there are a decent amount of options for your $2000 however I'd suspect that in the near future you will become disatisfied and start changing things...you wind up with lots of stuff...or selling stuff cheap to be rid of them...and a much more costly system than it should cost.
If you're the patient type I'd suggest starting with a receiver and front speakers then adding to the system as you accumulate the money.
To buy a quality entry level receiver your going to spend $500 or so...perhaps up to $750...that is plenty for a very nice receiver.
A quality pair of front speakers will be much more pleasing that lots of less expensive speakers. A good pair of fronts should also go deep enough in the bass area to put off buying a sub for a bit...
I'm a Paradigm guy though have heard other wonderful speakers as well. I'd look at the Paradigm Studio 20's for fronts. They have a wonderful sound and go quite deep. They are not inexpensive at roughly $1300 per pair but with a $600 receiver and pair of 20's you...add in the cables you need and maybe inexpensive stands...are right at the $2000 budget and have a great system.
B+W, etc also make wonderful speakers.
I suggest doing some auditioning and buy the speakers that sound best to your ears.
You now have a great stereo system for tv, movies and music.
Now for the rest:
If you're satisfied with the bass responce of the fronts I'd buy a pair of surrounds next. The features of the receiver will allow for a decent surround sound from just the four speakers. Whether you buy a sub or center channel next is really up to you and how the system is working in your room.
The center really defines dialogue in tv and movies but the sub provides so much "richness" that it is hard to suggest what to get next.
If you decide on surrounds next and for instance you have the Studio 20's I'd suggest the Studio 10's to stay in the family and provide an excellant match.
I'd also stay with a Paradigm Studio center and sub of your choice.
None of them are inexpensive but at the end you will have an amazing system without spending a lot of money on "replacements/upgrades"...wish I'd of done it or had the same advice.
The brand of receiver is perhaps a bit easier than the speakers. The majority of us are all partial of the major brands...Pioneer, Onkyo, Yamaha, Denon, etc. While they all have a bit of a different sound they are all quality brands that will satisfy for a long time.
Speakers are an entirely different animal...but speakers that you don't like after a period of time in your room or buying the most, but inexpensive, speakers you can will soon prove very disatisfying.
Speakers you like/love can last for decades providing sonic happiness continuously and are worth the extra time and money it takes to buy them.
If you have to take a day trip or half day trip to drive to a shop that is a bit far away it will certainly be worth the time and effort in the long run.
Make a demo cd of your favorite songs...perhaps only 10 songs is fine...of varied genres and artists. Take that cd with you when you audtion receivers and speakers.
Be patient and take your time...you will be much happier in the long run.
Good luck and keep us informed.
