Personally, I'm not fond of the idea of subraces. IMHO, seemed to me to be a reorganization of stat modifiers and abilities so as to improve or modify them to work in certain race/class combos better.
Also, I'm not a fan of the idea of an "evil" subrace, like the duergar or drow. Then again, I'm not too fond of the practice of developing a new monster from synonyms of existing ones (or using them in different environments: underwater elves, subterranean gnomes, desert lizardfolk, etc.).
I think one of the key things that got to me was the ridiculous multitude of elven subraces in a fellow player's homebrew campaign, as well as the system created to account for "mixed-blood" characters (e.g., half-drow/half-aquatic elves, etc.). Became a bit of a math headache (less so with Skills & Powers ruleset), but still added to the overabundance of elves in any pre-3E D&D game.
For my homebrew, I'm pretty much sticking with the "core" races listed in the PHB. If a player wants his elf PC to look like a drow, then that's fine--stat-wise, the PC's just like a regular (high) elf, but the PC has jet black skin & white hair.
IMHO, I'd prefer to see races for D&D only have racial modifiers based on biological factors rather than social ones. For example, elves would have the stat modifiers, low-light vision, elf blood, sleep immunity, Spot & Listen bonuses, and other such "biological" modifiers, but lose the automatic proficiency with bows and swords, which is more of a cultural thing (i.e., growing up included regular, daily training with these weapons, not some sort of genetic gift that an elf gained in utero). Factors due to cultural backgrounds and such can simply be reflected through character creation--stat placement, selecting certain feats or skills, using certain times of equipment, or even describing the character with certain styles of dress, mannerisms, speech patterns, or physical features.
Jusst my thoughts & opinions on the matter.