(2nd part):
If you make the change now, you'll be able to get the following extra channels:
ITV2: mainly chat shows and repeats of programmes like '3rd Rock from the Sun' + some feature films.
BBC3: Comedies and documentaries (most of which have been on, or will be on, BBC1 or BBC2). (Evenings only)
BBC4: Documentaries & arts programmes plus occasional films. (Evenings only)
ITV3: Lots of re-runs of Poirot, Chicago Hope, Jeeves & Wooster, etc.
Sky Travel: Travel documentaries, etc.
UKTV History: History (and some wildlife) documentaries
More4: Documentaries, films, chat shows, comedy.
E4: Mainly American drama & comedy. (Repeated an hour later on E4+1).
ABC1: American comedy & drama. (Daytime only)
The Hits: Pop videos
UKTV Bright Ideas: Cookery, gardening, house makeovers, antiques.
ftn: Magic, hypnosis, hauntings, spiritualism = some more general stuff. (Evenings only)
TMF: Pop videos, celebrity documentaries, etc.
ITV4: Crime series, dramas + some sport. (Evenings only)
Men & Motors: Cars, police chases, 'The Sweeney', etc.
CBBC: Kids programmes (Daytime only)
CBeebies: Pre-school kids programmes. (Daytime only).
BBC News 24: Rolling news.
ITV News: Rolling news.
Sky News: Rolling news.
Sky Sports News: Rolling sports news.
BBC Parliament: Live coverage from the Houses of Commons & Lords.
Community: Documentaries, etc about charities, etc (Early morning only)
Teachers TV: Schools programmmes. (MIddle of the night only!).
Also 4 shopping channels, Channel 5 (if you can't already get a decent signal), plus loads of radio channels (including the wonderful BBC7 - lots of classic BBC comedy + drama + kids programmes) and text-based services.
Time to change, perhaps?
Chris