If you want to ignore the SD channels altogether that have HD counterparts - then go to menu-5-2 and lock all the duplicate channels and all the SD versions of the HD channels. Then lock the system and hide locked channels.
Then you'll have only what you really want to see in the channel list, save on searching through a bunch of junk (duplicates). That way it doesn't matter what guide mode you are in. Just don't lock a channel that you'd want to watch. As a general rule the channels above the 400's can be locked out (for me). You obviously don't want to lock the music channels if you want to keep them, but the 4 digit channels mostly have mapped down versions. It might be better to wait to do a thorough lock until after you really know what channels you want. The grouping in the 3 digit range is more sensible than in the 4 digit range (from my experience).
Obvious things to lock (for me) are: shopping, advertisement, BTV's, info's, unsubscribed movie channels, SD PPV, PPV sports, adult, duplicates, foreign language, all unsubscribed channels, the gay channel...