It's difficult for me to answer this. Perhaps I'll start by saying that names like Rolex, Patek Phillippe, etc., aren't my main focus. The first watches I ever started to collect seriously were American railroad watches, and this happened purely by accident when I was given an Elgin 571 "B.W. Raymond" RR grade watch:
The case for this was very brassed when I got it, and the bow was a bad replacement - but I thought the movement was wonderful. I couldn't imagine that a factory-produced object could be turned out to such a standard - 21 jewels, 8 adjustments, subtle damaskeening, wonderful dial, etc. I went to the expense of having a proper bow hand-made for it, and then got the casemaker to re-gild the brassed case. And what I saw in this watch, I look for to be in my "keepers" ever since: good, practical design, good workmanship, solid, well-finished construction, no unncecessary frills, etc.