I wear a Seiko 5 automatic as my regular watch. However, for my dress watch, I use a gold Bucherer automatic that belonged to my grandfather (and, despite being made in the late '60s or early '70s, still keeps REALLY good time).
However, when it comes to my timekeeping pride and joy, there's my great-grandfather's Waltham 610 pocket watch - it's been in the family since at least 1910, it was made in 1899, and it keeps good time. It sits beside my computer as I work, this little piece of the 19th Century, ticking happily away...I cannot express in words just how amazing cool that is...
(Funny story about the Waltham - when my father gave it to me, he thought it was overwound. As it turns out, my father had just never given it the regular maintenance any mechanical watch requires. So, I got to tell my dad, who loves cars, that watches need oil changes too...)