A halfdrow obviously has a harder time getting a friendly word out of someone than a halfelf would. It would have to be more suspicious, checking people out (Sense Motive) and occasionally have to fend for himself (Survival).
Okay, changed stuff around. Halfdrow are now like halfelves except for the vision and the skills. How about:
Half-Drow
• Medium: As Medium creatures, half-drow have no special bonuses or penalties due to their size.
• Half-drow base land speed is 30 feet.
• Immunity to sleep spells and similar magical effects, and a +2 racial bonus on saving throws against enchantment spells or effects.
• Darkvision: Half-drow can see in the dark up to 60 feet. Darkvision is black and white only, but it is otherwise like normal sight, and half-drow can function just fine with no light at all.
• +1 racial bonus on Listen, Search, and Spot checks.
• +2 racial bonus on Sense Motive and Survival checks.
• Elven Blood: For all effects related to race, a half-drow is considered an elf.
• Automatic Languages: Common and Elven. Bonus Languages: Any (other than secret languages, such as Druidic).
• Favored Class: Any. When determining whether a multiclass half-drow takes an experience point penalty, her highest-level class does not count.
Elf-Drow
• +2 Charisma, -2 Constitution.
• Medium: As Medium creatures, elf-drow have no special bonuses or penalties due to their size.
• Elf-drow base land speed is 30 feet.
• Immunity to magic sleep effects, and a +2 racial saving throw bonus against enchantment spells or effects.
• Superior Low-Light Vision: An elf-drow can see four times as far as a human in starlight, moonlight, torchlight, and similar conditions of poor illumination. She retains the ability to distinguish color and detail under these conditions.
• Weapon Proficiency: Elf-drow receive the Martial Weapon Proficiency feats for the short sword, rapier, shortbow (including composite shortbow), and hand crossbow as bonus feats.
• +2 racial bonus on Listen, Search, and Spot checks. An elf-drow who merely passes within 5 feet of a secret or concealed door is entitled to a Search check to notice it as if she were actively looking for it.
• Elven Blood: For all effects related to race, an elf-drow is considered an elf.
• Automatic Languages: Common and Elven. Bonus Languages: Abyssal, Aquan, Draconic, Drow Sign Language, Gnoll, Gnome, Goblin, Kuo-toan, Orc, Sylvan and Undercommon.
• Favored Class: Cleric (Female) or Wizard (Male). A multiclass female elf-drow 's cleric class does not count when determining whether she takes an experience point penalty for multiclassing. A multiclass male elf-drow 's wizard class does not count when determining whether he takes an experience point penalty for multiclassing.