I don't usually collect fancy serial numbers unless they are pretty rare to see, such as 00000001, etc. It would all depend if you like the note that I recommend purchasing one. AS for the black eagle, that is (obviously) my favorite note. I have one in decent condition that can be viewed here: http://www.cointalk.com/t145914-8/ . I beleive I paid about half of what it is worth in XF condition, but they can be expensive depending on the signatures and grade.
Finally some of my currency is arriving Today received 1963 $ 1 Bill Mpc 472 10 cents Started a new ablum in my profile Currency Sandy