I only owned N64 <and then PS2> so N64 all the way.
But when you have a family as big as mine
<about 13 people live in a two floors + a basement and then some>
party systems are the only thing that would keep bruises off of those who tried to take the controller from me. =D
Yep it was indeed a party system, it didn't require a extra adapter to allow 4 players to play together unlike most consoles *coughs* all the Sony consoles...
What sucked though, was that you had to buy a rumble pack for each controller, and the PS controllers had it integrated, but if I'm not mistaken the N64's rumble was superior.
Microsoft made a good move implementing that in their system as well.
PS1 has to have my vote, I still remember the days I opened that present and played Heart Of Darkness for 12 hours straight on that little PS1... Now I can't even stand looking at one of those things hehe.