While I've had problems (data feed, unexpected quits) with Weathermenu from time to time, I still find it the most usable of any weather-related menu bar out there. (I've paid for several of them.) Note: For those with 10.4 security update issues, I have not, however, updated from Panther to Tiger.
For those having problems with this app, I strongly encourage folks to check out the AfterTen forums. You can often find early releases that fix identified problems, tips/suggestions from users, and finally revision status from the developer.