Add a redirect path setting

I think there should be a setting where you could specify the path to redirect to after login, like the front page.

I would like for my Administrators to be able to masquerade as Customers (a different role). So I would like to add a block somewhere for admins instead of having to drop it into a region somewhere on the front end. Maybe place the block on the dashboard at admin/dashboard. But Customers can not see the admin theme so when the login from the block occurs, the page loads again and it gives a permission denied.

Actual problem: When an Admin that can see the admin theme (permissions wise) masquerades from admin/dashboard, admin/dashboard tries to load immediately which throws an infinite loop due to some access callback returning false (I believe).

I can write a patch if need be.