Thanks for the input everybody; here is some clarification around the debt. The 50K was borrowed to purchase our duplex, the term is 5% with a balloon at 2015; we expect to have cash on hand at that point, but also have a HELOC at 6% that we can use in case we tie our cash up in another RE investment. This means that except for the car and credit card 100% of our debt is RE, and some of it is producing a nice return on investment. The car is at 3.9%, so while we will have paid down 38K of debt between June 2012 and Jan 1 2013, we would pay that last because it is the cheapest loan we have. Whew! (Mrs. PoP here - we treat the credit card as a revolving LOC and have never paid interest on them - the $1.4K balance on that sheet is just what was on the line at the point in time that the balance sheet was created.)
The points about flint and the marginal difference are very valid; this is a 10/10ths solution with the added benefit of owning something I consider aesthetically pleasing. In normal listening conditions (radio, movies) the extra fidelity will be wasted, but when I turn off the lights, crack a beer and listen to one of my favorite albums front to back...maybe not. It is a luxury, albeit one that I would enjoy for a very, very long time. Just to be clear, the price of the amp has nothing to do with how loud it gets =)
Cost per hour of listening is interesting, currently I probably listen to my headphones for 45 (Mrs. PoP says it's more like 90!) minutes a night (average). If I had purchased these amps 10 years ago, when they were 1500(!), I would have paid 150$ a year for using them thus far, or about...41 cents a night, roughly a penny a minute? Feel free to double check the math, but I think that is the ballpark.
Opportunity cost... Well, if we didn't buy this, we would using the money to be pay off a debt that is currently at 6% which is being paid down at a rate of about $4K in principal each month. Right now, total payoff on that loan is about 2 months out, so buying this would push it to about 2.5 months. Carrying the extra $2K at 6% for 2.5 months is about $25.
One of the saddest things I have ever seen was a retired doctor, now in his 80's, who had spent years collecting audiophile records...only to have gone deaf over the last 10 or so years of his life. He told me it wasn't the money, it was that he would never again be able to hear the music.
@Mrs. MM, Tell MMM to be careful in Oahu-the last time I was there I meant to stay for a month, but would up staying for 6!