I have only owned one Porsche (my current), but I'll play:
#1 - 959 - Way ahead of its time, and this thing is still a modern supercar by many standards.
#2 - The new 911R - Saw one yesterday - very cool.
#3 - 993 Carrera 4 - Air-cooled, all-wheel drive, and certainly more attainable than a 959.
#4 - The '75 Targa in my garage.
#5 - Cayman (post IMS issues, of course) - In my opinion, the most "bang for the buck" you can get in a used Porsche.
#6 - 908 - Anything with 8 cylinders and a required rear elevator/flaps to keep the wheels planted deserves to be on the list.
#7 - 906 / 904 - These things just oozes "old-school cool"
#8 - 917 - These solidified Porsche racing dominance
#9 - The classic 356 - Motoring in style
#10 - 935 - Can you imagine the grin on the first Porsche test driver who got the turbos wide open for the first time?