I've been having some problems, too. I have two WAPs with WPA2/PSK so I have full signal availability throughout my house, but every other time it seems like the N800 can't seem to get connected.

Another recent problem is that after charging, some of my tray icons disappear. I'm wondering if there's a flakey application (omweather, advanced backlight, large-status-bar clock, load-applet, maemo-control, maemo-control-services, maemo-control-usb) or something?

** UPDATE ***

Summary: WiFi repeatedly won't connect and times out on N800 with Diablo (latest).

Suspicions: I think that the WiFi connection status is left in an indeterminate state by one or more applications and doesn't get reset properly.

Why do I suspect this? WiFi connection is fast and immediate after fresh reboot. If I set mode to OFFLINE and then change to ONLINE, connection is fast and immediate. Therefore I think that selecting Disconnect at the end of my normal browsing sessions doesn't clear or reset some variables somewhere.

Anyone else with observations on this behavior?