how much would you say a good set up cost

I think Tvad recommended two excellent combinations that would be very rewarding (Merlin/Ars Sonum or Audiokinesis/Atma-sphere)at the 10K level used - those combos would beat a lot of 30k systems IMHO.

If you can't put together a fantastic system for 30k it requires a lot of missteps, not that you couldn't have a mediocre system with that much money into it (you can). But I agree with the general tenor of the thread that with 10K or less you could (expecially buying used)put together a very formidable system, especially if you know what you are doing with matching a speaker and amp. If you have been around the block with this hobby, you can do so easily. Without that experience or the advice of a good dealer or experienced friend, you can chase your tail in this hobby and spend a whole lot more without getting a system that will satisfy for the long term.

Tvad's 10k system (Merlin,Ars, Rega) would be very, very good and comparable to most anything out there except for full range bass - but that system combo is one I would hghly endorse for bang for the buck.

I think that at 30-35k you could build a system that would be hard to beat no matter how much more you would be willing to spend, assuming you know what you are doing, but I still think I could come very, very close at 10K used, and could certainly put together an extemely good sound system for less than 5k, and as Jax2 suggests, even that amount of money would be considered innsane by most folks, but reasonable by folks on this forum. So to ansswer the OP, $5k should certainly get you a "good set up". The rest is fun and games that come with being into the hobby IMHO.

My point to some extent is that while many on this site may be able to spend 30k, that even if you have the money -there is no need to spend that much for a very excellent system (I should talk). SOTA is an elusive idea to me, but I know that you can have excellent sound for 10k or less. For example, I think that the recommedation made earlier of Merlin VSMs with an Ars Sonum integrated would be more than impressive to most listeners, even experienced Audiogon folks - it is a very well sorted speaker with an amp practically designed to drive them - true, proabably closer to 10k used, but a pairing that a few folks with former 40k systems have come to own for reasons other than limited $$$. Cost no object doesn't always mean better sound (though obviously it can). I heard a few CNO systems at RMAF'08 that I would not want in my listening room compared with my more "humble" system. Experience and understanding how to put a system together is a very valuable form of currency.