My suggestion would be to have the station logo/icons available in the guide. I live in Chicago and have ComCast and the organization of the channels is quite ridiculous.
Example: our NBC affiliate is WMAQ, broadcast channel is 5 and referred to throughout the area as NBC5. Comcast lists their channel (as does TiVo) as WMAQHD on channel 188. I'm not one to memorize channels so any visual clue as to where the channels are would help.
ABC is ABC7 but the HD channel is on 189 (kind of makes sense with the last digit as 9) but CBS2 is on 189.
I have to say that the guide on the iPad app is great and would be nice if it was mirrored on the TiVo iteself. I can find the channels very quick with the logos but not everyone in my family wants to use the iPad. They just want to use the TiVo.