I don't think the Canucks should retire his number, but they should honour him.
There are only 98 numbers you can give out, so if 1 is actually forever locked, that person might have done something really spectacular (long playoff run).
Do the Canadiens or TML actually retire numbers? I mean since they've been around forever, you'd assume there won't be too many numbers left for players on the team.
Vancouver should just honour his name by like creating a separate "jersey" hanging, where the number is still in use and therefore isn't quite as high as like #12 or #16, but it will give fans a chance to celebrate Naslund's accomplishments.
Also, is Markus Naslund retiring from just the NHL or hockey in general? I would assume he would maybe like to play a couple of more years for MODO, make his way onto the 2010 team and then slowly ease into retirement.