The Legend of Link is the best Zelda hack out there by a country mile in my opinion. It's the most impressive NES hack I've seen to date. You can't put it on a Powerpak though due to its sheer size:
http://www.romhacking.net/hacks/2...
Flashback used to sell a limited quantity of NES carts with this hack, but they're all sold out now. I doubt they'll make more of them. I think Clarky here on Nintendoage makes a Famicom cart version of the hack though:
http://clarkycreations.com/index....
It should play just fine through that extra Famicom slot in your Nt.
Super Mario Bros 3 Mix is another hack you really should check out too. And unlike Legend of Link it'll work on your Powerpark: