The only real race descrimination you'll come across in-game is from the NPCs. I've noticed that there are always hardcore nationalists in Windurst, San d'Oria, and Bastok. However, in San d'Oria most all NPCs seem to be racist, but you get over that quickly.

As an Elvaan I occasionally went into Elvaan-supremacy mode, but that was mainly in playful linkshell arguments over what race was best.

As a taru, I do act quite silly. I have a set of macros for emotes including things such as giggle, huggle, and the taru panic dance. I don't speak like a taru NPC often, but I do generally act a little childish. I suppose it just happens naturally that you end up playing the part.

I've noticed that people seem to care less and less about race/job combinations as they level up and there are always factors that will over-ride any doubts of your capabilities.

I've played as a taru WAR and now I'm playing taru DRK and I've never had any real trouble getting a party. As a WAR I was the main tank on many occasions and I did just fine.

As long as you can show that you know what you're doing (use search comments, use food, keep up to date with equipment, and raise your rank at the appropriate times) nobody will have any reason to hate on you because of your race or your job. Except maybe those Elvaan NPCs.