I'm bored... so I've gathered all the
official names in print.
Official sources (in descending priority of override top to bottom):
1. The Manga & the Perfect Guide Book
2. Sony @
http://www.sonymusic.co.jp/Animation/hagaren/
3. The Anime & its DVDs
5. Animage (an anime guide, ala TV Guide)
5. NewType (same as Animage but uses less English names)
So let's start off.
The Elrics
Edward Elric (All)
Alphonse Elric (All)
Trisha Elric (Sony, DVD)
Hohemheim Elric (Anime)
The Rockbells
Winry Rockbell (All)
Pinako Rockbell (Sony)
Sara Rockbell (Anime)
Den (DVD)
The Curtis & gang
Izumi Curtis (Manga, Sony, DVD)
Sigu Curtis (Perfect Guide Book, Sony, DVD)
Meisun (Sony, DVD)
Our local Scooby gang
Roy Mustang (All)
Riza Hawkeye (All)
Alex Louis Armstrong (All)
Jean Havoc (Sony), Jan Havoc (Animage)
- Jean = French, Jan = Danish, same pronunciation same connatation. I would take this discrepancy under the same reasoning between "Brandon" & "Blandon" 
Heymans Breda (Sony, DVD)
Vato Falman (Sony, DVD)
Kain Fuery (Sony, DVD)
The Hughes
Maes Hughes (All)
Glacier Hughes (Sony, DVD)
Elicia Hughes (Sony, DVD)
Other military folk
King Bradley (All), Fuhrer (Anime), President (Anime)
- a curiousity in terms that he seems to have two official ranks. But easily explained. Fuhrer is his rank as the Commander in Chief of the military. President is his office when in the position of leader of the country (for non-military policies).
Basque Grand (Sony, DVD)
Kimblee (Animage, NewType)
Frank Archer (Animage, NewType)
Maria Ross (All)
Denny Brosh (Sony, DVD)
Tim Marcoh (All)
Sheska (Sony, DVD)
The Homunculi known as Sins (in order of appearance)
Lust
Gluttony
Envy
Sloth
Greed
Wrath
Greed's Chimerae
Martel (DVD)
Roa (DVD)
Dolcetto (DVD)
Ishuvaruns (Ishuvaru is a romaji, not the actual English name)
Scar (All)
Rick (Sony, DVD)
Leo (Sony, DVD)
Episode 1
Rose (Sony, DVD)
Cornello (Sony, DVD)
Cray (Sony, DVD)
Episode 4
Majhal (Sony, DVD)
Clause (Sony, DVD)
Episode 5
Bald (Sony, DVD)
The Tuckers
Shou Tucker (Sony, DVD)
Nina Tucker (Sony, DVD)
Alexander (Sony, DVD)
Episode 8
Barry the Chopper (Sony, DVD)
Episode 9 @ Youswell
Yoki (Sony, DVD)
Lyra (Sony, DVD)
Halling (Sony, DVD)
Khayal (DVD)
Episode 10 @ Aquroya
Clara aka Siren (Sony, DVD)
Episode 11
Russell Tlingum/Tringum (Sony/DVD)
Fletcher Tlingum/Tringum (Sony/DVD)
Nash Tlingum (Sony, DVD)
Mugear (Sony), Mugwar (DVD)
Belsio (Sony, DVD)
Elisa (Sony, DVD)
Episode 26 @ Rush Valley
Paninya (Sony, DVD)
Dominic LeCoulte (Sony, DVD)
Geography
Amestris (Manga)
Aorugo (Manga)
Aquroya (Anime only)
Central City (Manga)
Creta (Manga)
Dublith (Manga)
Drachma (Manga)
Youswell (Manga)
East City (Manga)
South City (Manga)
New Optain (Manga)
Resembool (Anime)
Rush Valley (Manga)
Xing (Manga)