This is the best one I've seen out there so far. Has everything and with a couple of minor Order of Precedence glitches when selecting multiple services, gets it right.
http://www.medals.pl/us/ (http://www.medals.pl/us/)
That is a good one. Most of the folks here have been using it for a few years now.
For multiple branches, it looks to use the DOD order of precedence. I think the DOD order was established based on the "birthdates" of the various branches.