TiVo has just introduced the TiVo HD XL, an upgraded version of the TiVo HD DVR that I've got, with much
more storage. For $600 compared to the current model's $300, you get 150 hours of HD recording on a 1TB hard drive, compared to 20 hours, plus the Glo Remote and THX certification that came with the (originally) $800 Series3.
If I were looking for a new HD--capable TiVo right now, this is unquestionably the model I'd get. It's got plenty of storage capacity, considerably more even than my TiVo HD plus the Western Digital external My DVR Expander I added to it.
Available "now" (but not yet) at TiVo.com and soon from Amazon and other retailers. (Image swiped from ZNF for now.)