Update: I've done a few things with my wi-fi AP and at least one of these measures seems to have helped, as I've not seen the problem since:
* Turned off 802.11b/g/n, turned on 802.11g only
* Turned off QoS
* Changed wi-fi channel to 5
* Added a second AP also set to 802.11g only (same SSID, channel 8)
According to the phone's wi-fi signal strength display I shouldn't have needed the second AP, but with it I definitely have a much stronger signal all over my house. BandWidth shows a speed bump from ~5M to around ~10M.
So maybe the Titan is very sensitive to signal strength? Or doesn't like 802.11n. Or maybe it just doesn't like the Belkin router I have.
I'll be trying this at work tomorrow to get even more data points. I use this thing on GoPhone and so non-reliable wi-fi --> the Titan is going back.