The most important word of advise?

Don't let your wife or significant other dictate what you buy. They get to pick the drapes, furniture, etc. They have no business making audio-centric decisions. Be a man
for once in your life...

-RW-

Put your money in your speakers first. Build your system around them. They are, ultimately, where the music comes out. I know this will generate some controversy, but that is where I would start.

When you listen (you are going to listen before you buy anything, aren't you?), beware of "impressive sound".

In case that needs clarification: sound that somehow directs your attention to how extended the highs are, or how much bass there is, or whatever element you care to pick out, is in my very humble experience, never a good sign.

The kind of sound I can live with takes its place in the room like a normal person and speaks at a normal level, and if you don't pay attention to it at first it doesn't try and grab you... but when you open up to it, it dances with you. I find myself moving, toes tapping maybe. It's physical.

Music is more important than equiptment.

I couldn't limit the advice to just one item of importance. However, I will limit it to just several of the most important.

1. Start with being reasonable about what the size of your room will accommodate and choose speakers accordingly. Those big floor speakers may sound great, but not in that tiny, converted bedroom system. Only if you quickly intend to use them in a larger room should you consider floor models in a small room. Stand mount speakers will almost always get you closer to the music in small rooms.

2. Speakers and amplifiers should be chosen to be compatible with each other. A technical mistake in compatibility is a mistake that can only be undone by selling one or the other, usually at a substantial loss.

3. Proper speaker positioning is the single most important starting point and will effect the frequency response more than any other factor. Read and learn and know where they are going to go before you even audition.