Youngest stepdaughter has had two lots of rats as pets:
They are very friendly and sociable if you put the time and effort in. Will happily sit on shoulders/crawl around inside your clothing or happily play around you once used to their environment.
Distinct personalities, very rewarding and extremely intelligent creatures - a pleasure to be around.
Never taken one outside though - too scared of having to explain how I lost a favourite pet.
The big downside is the smell, unfortunately. They aren't continent and wee all over you, your house and your clothing as you handle them.
It's quite a pungent aroma too, so probably best to go and visit someone who keeps them as pets before commiting.
Just started working for a new client who has a Senegal Parrot as a pet.
Raised from a captive chick (as they all are these days) so very socialised and used to people - never thought of keeping a bird before due to the ethical issues, but must admit they are quite tempting -
more info here.
How about a house rabbit?
Had one for years and they really are wonderful pets.
House trainable, sociable, continent, intelligent and loads of fun.
Will chew cables and strip wallpaper, but very rewarding.