True story: One of our readers told me he has more than two dozen networked TiVos in his house; obviously he doesn't like to delete any of his recorded shows. This guy should definitely look into the TiVo HD XL ($599.99 list), the latest DVR from the company that made TV time-shifting all the rage. The XL is the spiritual successor to 2006's TiVo Series3 DVR. And the XL simply stands for lots of hard drive space—1TB to be exact, as opposed to the standard 160GB that the $300 TiVo HD offers. That extra space translates into about 150 hours of HD recording (up from 20 hours for the TiVo HD) and more than 1,360 hours of basic quality SD recording. That's a lot of hours of television, and you'd be hard pressed to catch up with your viewing once you built up a program library. So the device should satisfy most TV junkies—maybe even that reader with TiVos littering his living room.

The XL features the same 3.4-by-16.5-by-12.6-inch (HWD) chassis as the TiVo HD, and like the HD, it gives up the Series3's OLED info display on its front panel. The fully backlit TiVo Glo remote and THX certification differentiate the XL from the older HD model, but unless you're using the XL in a very expensive, high-end home-theater setup, you're unlikely to notice the THX improvements. The TiVo Glo remote is nice, but you can buy one for about $50 on TiVo.com, and it works with the cheaper TiVo HD just as well. The meat of the improvement is that huge 1TB hard drive. Since a bare 1TB SATA hard drive goes for $150 to $200 retail, the $300 price difference between the TiVo HD and XL can seem a little on the steep side. Yes, I realize it's not as simple as dropping a larger hard drive into a TiVo HD, but I have trouble swallowing the idea that a backlit remote and THX certification cost TiVo over $100.

Day-to-day use of the TiVo HD XL is the same as with any other TiVo model: The familiar, no-nonsense, easy-to-use interface is here, too. All three TiVos use the same version of the operating system, so you can access the Rhapsody music service, Amazon Unboxed service, and Yahoo! and YouTube content. Yes, you can watch YouTube on your TiVo, but it's more satisfying on your PC or on an iPod touch or iPhone. Blowing up YouTube video to HDTV size is a blocky and jerky experience at best; still, it's nice to have the ability to watch it on the XL, if you'd like.

You can also network additional TiVo units (Series2 and later). Recording programs was simple, and the CableCARDs I use with my Verizon FIOS TV connected easily and worked instantly. You'll need a CableCARD for each tuner if you want to record premium programming from HBO and Showtime, for example, but you can record unscrambled HDTV from cable or an antenna hookup straight out of the box.

Like the HD and the Series3, the XL features an eSATA port on the back. You can use the eSATA port to add an extra 60 hours of HD recording with external drives like the Western Digital My DVR Expander. Iomega also makes a similar TiVo-certified drive, the DVR Expander Drive, and users on the Web have reported success with larger external drives (though these noncertified drives take a few extra steps to activate).

A cool extra: I was able to download recorded shows to my Mac using the TiVo Transfer program in Roxio's Toast 9 Titanium. I was then able to transcode HD and SD programming to an H.264 format compatible with an iPhone or an iPod touch. Transcoded programs looked fine on the iPhone's small screen and played back in iTunes without any problems. Toast also has transcode presets for Apple TV and Sony PS3 playback.

TiVo service plans are clear-cut: You can choose to pay $12.99 per month, or $129 ($10.75 per month) a year if you prepay; $299 ($8.31 per month) for three years prepaid; or the legendary $399 Product Lifetime plan—which offers service for as long as you have your TiVo box. Remember that renting CableCARDs from your cable provider will cost a few dollars per month each as well. But if you use the XL for more than six years, the Lifetime plan makes more sense than a $12 per month cable box DVR. If your devices don't typically last that long, you may be better off with that cable-company-issued DVR. You just won't get the excellent TiVo interface.

Sure, the TiVo HD XL is an improvement over the TiVo HD, but ultimately, given its price, it's not all that compelling unless you record a lot of HD programming. My take: The $299 TiVo HD, with its sweet combination of features and an attractive price, is still the DVR champ. The $600 TiVo HD XL is likely to appeal to the hard-core TiVo fan who will actually use all that storage.