Well, I've been thinking of some extra ways of customizing characters, and I think I've come up with a few good ideas. Looking for some input.
Background bonuses: Since 4th Edition's pretty streamlined, it's sometimes hard for me to think of ways to put in little pieces of individuality for my characters. So, house rules to the rescue.
First, take the "standard" background bonuses available to characters: Two associated skills with the region/personal history/whatever background. You either get a +2 bonus to one or add it to your class skills.
The next bit is my idea: You get one background "quirk" for each tier of play. Paragon- and Epic-tier quirks are unique characteristics you've acquired over the course of adventuring. These quirks generally don't provide statistical bonuses, but the idea's broad enough to require DM approval. Some examples:
Elemental Prestidigitation: A good quirk for non-Wizard arcanists. Only usable in non-stressful situations. Example with my desert sorcerer: He gets "sand" as his element. He can do Prestidigitation-like abilities, so long as they involve sand, like conjuring a bed of sand to lie back on, forming sand sculptures that crumble once he stops concentrating, turning sand into rough glass objects, etcetera.
Daily Ritual: You can perform a chosen level 1 ritual once a day for free, possibly with restrictions. Example: I have a concept for a NPC wind-oriented Shaman who can perform the Animal Messenger ritual with birds.
Warforged Prosthetic: My desert sorcerer's paragon-tier quirk: He's a southpaw who lost his right arm to a werecroc and replaced it with a effigy look-alike. It doesn't give him any bonus to his ability scores like the old Arm of Nyr, but it does allow him to embed or attach Warforged components. He usually keeps an off-hand weapon embedded.
Bonus Language: It seems a bit off that there don't seem to be many ways to learn new languages.