Is it possible to use a trigger on a task to send an email notification to the task creator when the status changes to Completed?  I'm very frustrated that this is not possible using a workflow rule, but am holding out hope that we can accomplish with a trigger. 

I'm trying to add a lookup field on the user record that looks up to a filtered list of accounts.  There is no option to add a lookup filter.  Are there any options to set it up so that the picklist on the user record can mimic pulling it's values from a lookup?  I don't need the value in the field to be clickable, I just need it to be popluated with the same values that would be created by a lookup to account name.  I'm open to options using triggers, workflows or custom code.