Hi,

once upon a time there was a type-ahead search in Gossip over contact nicks and JID, when you want start a new conversation (CTRL+N). This is not available in Empathy and IIRC not in gossip anymore, too. I think this feature could be helpful to start conversation with offline/invisible users. At the moment I unhide offline contacts and search them, because it's so hard to type (and remember) a full JID. I guess the same with MSN-Contacts and ICQ-Numbers are even worse.

The actual "New Conversation" UI has two difficulties:
 * the mentioned typing of the full contact address 
 * choosing the correct account

Here my recommendations:

- add a type ahead search over nicknames and full identifier (like JID, MSN-ID, ICQ number)
- the search should over all active accounts by default.
- there should be a combobox showing the entry "All Accounts" where you could choose a specified accound if you wish.
- under the combobox should be a list (treeview-widget?) with all contacts matching the search
       - there could be additional information like icons showing if the contact support calling
       - contacts from protocols without support for offline messages ought be shown, but greyed out or deactive