Rawdogger, from Frontline Gaming and Blood Angels player has been running a Hot or Not set of articles for the blood angels. Give them a click through.
Command Squad (hot): Basically using them as a meltacide unit out of a drop pod is an embarrassment. The only way to run them is with your company captain to heroically strike back against the enemy tide. If you are going to paint those models up right, let them hold some focus on the battlefield for your enhanced pleasure.
Death Company (hot): This is a very, very personal choice as to how many brothers have fallen and have joined the Death Company. I recommend going light to heavier as you progress through a campaign or a set of narrative games. The blood lust will be building in your army as they continue the grind of war and see brothers fall in the field.
Lemartes (not): If you have decided against using an HQ slot for a chaplain, Lemartes is a nice compromise to add in with your Death Company. Opponents still may underestimate lower powered units or devote too many resources to killing them if they are feeder units.
Sanguinary Guard (not): If you are running Dante, the Sanguinary Guard should probably be there too. This is a rather awkward unit that was slipped into the 5th Edition codex and some unfortunate aesthetic choices- wings, nipples and even perhaps gold armour. Ideally, this unit is best seen as an apocalypse game unit led by Dante. You don't want to run them where they will be a prime focus by the enemy and see them wiped from the battle in one turn.
Dreadnought (not): Dreadnoughts are pretty iconic, so don't forget to run one every once in a while. It may actually be a pretty nice counter attack unit (assault cannon, dccw), so don't be afraid to use unconventional units for certain battlefield roles. You know your units, so use that to your advantage for deception and keeping your opponent off-balance.