There is a link to an article over at dslreports.com about how Sprint is going to require all new smart phones (after the Tour) to have WiFi. This includes the Tour II do out early next year.
I find wifi very important. As smart phones get more media rich, we will start butting our head up against the 5 gig threshold. If you move your home and office internet usage to wifi, this will greatly reduce the burden.
Wifi also provides good backup coverage where you have poor cell coverage. Contrary to Verizon's advertising, there are many places that don't have good coverage around the U.S.
Wifi reduces your international data roaming bills (and possibly your voice roaming as well). In addition to this, international roaming is not perfect. Earlier this year, my wife couldn't get roaming coverage working for seven days with TMobile. What would have been a disaster became only a minor incident because she had wifi in the hotel room (courtesy of a Linksys portable router) and at the client site.
Besides Sprint and Verizon's bias against wifi, they have clearly had problems getting wifi into CDMA/GSM combination phones. With respect to the Storm, the Tour (compare it to the wifi enabled Curve 8900 and the Bold), and several other phones. If you travel internationally and want a global roaming plan, there are only a handful of non-Blackberry options. [But go look at the Apple forum at ATT's company run forum forum.wireless.att.com) where there is discussion of a little known corporate ("FAN") nearly worldwide unlimited iPhone plan]