I was wondering what differences there are between Space Marine chapters when it comes to the card decks, so I collected all the cards for every character. Here they are:
What I have picked up from the cards alone (not tested yet):
The first card on every character depends on the chosen weapon (where possible).
Blood Angels: good at close combat (duh!). Sergeant and Librarian almost mandatory, Assault good, Apo optional, could do without a Heavy, although some cards let your termies walk through fire so a heavy flamer could be nice.
Dark Angels: good shooting and excellent Librarian (must-pick). Sergeant and Assault might be better with bolters but not must-picks, Apo has some nice cards, Heavy with plasma will shoot for days.
Space Wolves: good at close combat, but better in packs. I would bring Sergeant Librarian and Apo, and potentially ditch the Heavy in favour of 2 Assaults. Sergeant has the only +5AP convert card for Space Marines.
Ultramarines: good at range and at drawing lots of cards. Many cards provide immunity to jams/malfunction. Sergeant not a must-pick, Librarian and Apo look good, Assault better with a bolter, Heavy is alright.
I hope this helps someone! If nothing else, it did help me. Lots of testing to do now... Have fun!