FIXED!
I fixed two long standing problems at once today. First, upgrading to the latest FC5 kernel (which happens to be based off of 2.6.17.1) finally fixed the wifi problems on Denise's laptop. This crap had been plaguing us since upgrading to FC5 about two months ago. Now, it just works. No more nonsense of removing and reinserting the wifi card at bootup just to get it to properly associate with the access point.
Second, I purchased a Linksys WRT54GL router/wifi-AP. My old (its about 3.5 years old) Belkin 802.11b access point was starting to get unreliable. It didn't want to send traffic from local, wired systems to local wifi systems. Also, its range seemed to have decreased significantly in the past few months to the extent that I was seeing close to 90% packet loss on David's computer. With the new WRT54GL both of those problems are now eliminated.