Contacts fixes (that I remember being working on: that doesn't necessarily mean they made it into the release in the end):

• Disabling an IM account should not remove contacts that are also in groups
• Contact picker is now faster at listing contacts
• Faster searching for contacts in Chinese (& some other asian locales)
• Editing certain imported contact fields is now possible (it wasn't, in a few cases before)
• Importing IM contacts should be a bit faster (& less resource/battery intensive)
• Various other reliability/smaller misc fixes