Here are some points to keep things clear (I hope).

DirecTiVo gets all updates via its satelite connection. The phone connection is merely to collect data on your watching behavior and to order Pay-Per-View. You can order Pay-Per-View manually with a voice call instead, BUT, the TiVo will keep a counter of how many days it's been since its last service call. Once too many days have passed, it will disable the TiVo service.* TiVo service is the ability to use the program database to schedule and record. *this may be different with newer versions of the TiVo system software - you may only get a nag without having service suspended. In all cases, the TiVo can be fooled into thinking it has made a successful call by way of a hack - there are multiple different ways to accomplish this. Been there and done that (both cases) with my Philips DSR6000 series1 DirecTiVo running software versions 2.5.x and 3.1.x

USB ports on Series2 Stand-Alone units work out of the box. On DirecTivo they are NOT enabled by the system software installed on the units. I believe they can be enabled via hacks.

With Ethernet enabled on a Stand-Alone TiVo (any) you can use a special call prefix (I believe it's #401) to make the TiVo do its daily call over Ethernet. This downloads guide data which would otherwise come over the phone. I can't recall if this works on a DirecTiVo in place of the service call.

Another difference between Stand-Alone and "DirecTV with TiVo" is that series2 Stand-Alone TiVo boxes come with HMO (Home Media Option - aka streaming content from PC) enabled as part of the monthly subscription. This is NOT available on DirecTiVo units even with the most current software updates. DirecTiVo units (at least standard-def ones) are all dual-tuner. There are no dual-tuner Stand-Alone boxes (which sucks big time).

Phew. Personally, I think the future looks somewhat bleak for TiVo. Regardless of how much I like their product, I don't believe they have what it takes to stay alive in a market that's only getting mroe competetive and where (some of) the other players are adapting and moving (much) faster along with industry trends.

Bruno