Why not multiple choices ? I said Dwarf also.
I'll consider each race for the purpose of making a melee Fighter (not a melee combattant, but a Fighter) that is not adverse to multiclass latter, but want to stay primarily fighter.
My reasoning is similar:
+2 Con (good), favored class, Darkvision, but also +1 to hit common foes that drop quickly (orcs and goblinoids) and +4 to dodge common foes that drop you quickly (giants). Biggest drawback of the dwarf: his slow speed. This can prevent him from reaching melee quickly enough.
The Elf could be a good finesse fighter in the absolute, however he isn't really interesting. -2 Con. Ouch. Plus, he don't get any real bonus to combat, contrarily to the dwarf or gnome (against some enemies) or halfling (with some weapons). The automatic proficiency in bows and longsword or rapier is of no utility to a fighter.
The Gnome would, by the same token as the dwarf, seem appropriate also (+4 dodge against giant, +1 to hit kobolds and goblinoids -- or even orcs, goblinoids, and all reptilian humanoids if you go forest gnome), but the -2 Str and smaller weapons hurts too much for a melee specialist for the +1 to AC and all attacks to compensate.
The Half-Elf don't seems really interesting for a fighter. He don't have any fighterish racial ability, not even a bonus to a good fighter stat (Str, Dex and Con).
The Half-Orc is a perfect melee fighter. He's made only for that. He would come in close second to the dwarf. His primary drawback is poor Int -- can't compensate the scarcity of skill points for fighters -- and also, lack of miscellaneous abilities. The half-orc is the only race that is characterised by only stat adjustments and darkvision (and yeah, orc blood). All others have bonus to this and that or other special traits.
The Halfling suffer from the same problems, and have less advantages (for this role). A good halfling melee fighter is a rogue, not a fighter, because without sneak attack, his damage won't be high enough.
Last but not least, the Human is a very good choice also. No malus, any favored class, bonus feat and skill points. His bonus skill points compensate the fighter's weakness, and his bonus feat allow a faster progression in the feat chains. Rather than being redundant with the fighter bonus feat, the human bonus feat is really a boon for a fighter. The drawback of the human is poor sight (especially bad in darkness, but also hampering at night-time -- having low-light vision would allow the melee specialist to see exactly where are the ambushing archers and charge them) and lack of good fighter stat.
So, to sum up, it's a near tie between Dwarf, Half-Orc and Human. All other races are better suited for other classes, and/or for ranged fighter.
Edit: Looking at the poll result, for now, only dwarf, human and half-orc have been voted.
