Mike's asking the right questions, but here are my reactions...
I'm roughly your size and ability...Midwest running 400 vertical. I sky the following here and out west.
Rossi Black Ops 98 - favorite all around. Ski it everywhere.
Kästle 89's - just purchased, been demoing friends. Love it for here and will use it frontside outwest. Ski is in a totally different class of ski.
Salomon QST 99 only ski out west. It's fun and forgiving but light and chatters. Good for primarily soft. The Rossi is above is good for almost everything I ski but deep. But then I would rent deep.
Of your list, I've demo skied
Enforcer 100 - fun, meets your criteria, possibly the best candidate here to have for fun and handle most powder up to 6-10 depending on ability. Different than what you're using.
K2 Mindbender Ti. Different ski to me, I couldn't get into it. I'm just not sure why.
Elan Ripstick 96, 180 - consider Black Edition. FUN.
Blizzard Rustler 9 - different ski, one of my favorites. Stable. awesome. Different than the Enforcers.
I don't own a dedicated powder ski (Would rent instead) so of your list, I would probably want the Blizzard for myself since I would want to cover most conditions other than moderate to deep powder since I would rent anyway. I also like ripping on groomers and don't like chatter in crud. Blizzard ski and brand just delivers. It's different than the rest though. You could also possibly pull this one and the Elan 96 out at home as well.
But with all that said, given your destinations and your plans to shelve it other than west trips, and if you want different than you're used too, probably Enforcer 100.
The Fun Factor defintely plays into this - the Ripsticks end up with that type of commentary pretty regularly...