I'm currently a ranger in The Red Hand of Doom adventure, but if that character dies, I'm considering playing a diplomat.
Half-elf bard 5
Cha 20 (cloak of charisma +2)
Diplomacy 8 ranks
+6 synergy from Bluff, Knowledge (nobility & royalty), Sense Motive
+2 racial
+2 Negotiator
+3 Skill Focus
+5 custom magic item of Diplomacy bonus (2500 gp)
+2 masterwork tool of diplomacy
5+8+6+2+2+3+5+2 = +33.
Oh, you're hostile? Give me a full round action and you'll be at least unfriendly, and probably indifferent, maybe even friendly.
64 skill points (8/level with 14 Int), -32 to max out Diplomacy, Bluff, Knowledge (nobility & royalty), and Sense Motive, leaves me with 32 languages.
Or maybe I'll take 24 languages and max out Disguise. Oh, okay, 16 languages and I'll actually have ranks in Perform (oratory).