You can get a lot of stereo for $4000. Keep in mind that it will sound very different at home than in a store. Don't be afraid to drag an amp and pre around to test speakers or even bring gear home to try on your speakers.
I'd revamp the entire system. Spend equally on each piece. Do you need dvd instead of cd? Most blue ray players make excellent cd players. Speakers have changed a lot in 20 years. Small satellites with or without a sub can be great. Don't get cheap on the stands though. Finally, do you want radio? You can always add a really cheap tuner but it may be much cleaner to be built into a pre.
I'd revamp the entire system. Spend equally on each piece. Do you need dvd instead of cd? Most blue ray players make excellent cd players. Speakers have changed a lot in 20 years. Small satellites with or without a sub can be great. Don't get cheap on the stands though. Finally, do you want radio? You can always add a really cheap tuner but it may be much cleaner to be built into a pre.