Plunkett & Macleane falls into my favourite genre of film (historical action adventure with comedy) which is probably why I rate it so highly.
The action centres around a highwayman (Plunkett) and a layabout 'gentleman' who gets entangled with him and his schemes (Macleane). This leads to all sorts of escapades and adventures which are all tinged with comedy. There is also, of course, a love interest.
The rest of the cast is made up of a number of vibrant, larger than life characters who add to the atmosphere of the film and show the excesses of the wealthy at this time.
This is an enjoyable film with a fairly simple but worthwhile plot that provides plenty of entertainment.