In your case, buying used but well-maintained equipment will virtually double your budget. Just as tomcarr said above (good analogy to underwear, I will have to remember that one).
Now, what equipment to buy is more difficult to decide. At least for speakers, listen to them first if you can. For example, no review and no person seems to have ever disliked above-mentioned Pioneers. Statistically they may be the best buy you could ever have. Had I bought them for myself, they would have been the biggest disappointment ever. I bought them for a friend of mine and he was beyond satisfied which is what really mattered. I am just trying to say "approach carefully and try to hear first". At least for speakers. For your budget, Monitor Audio has a good price/quality ratio in my opinion. They can be found used and in great condition for relatively little money.
Also, what kind of system are you really envisioning? Plain two channel, sitting in front of it and just listening, or something that would eventually involve movies and, maybe, surround?