I have mine set to:
On Battery: Neither WiFi nor remote ever turn off, backlight 1 minute
On Cradle: Wifi never & Nevo off after 30 minutes

I have been moderately annoyed by the waking/re-establishing of WiFi, but with these settings that's not an issue at all....ever. On the flip side, with these settings I worried about battery life. However after 2-3 hours of watching TiVo & intermittently toying around with the Nevo, I couldn't tell one ounce of energy had fallen off my battery indicator (hope its accurate).