Well, i advise against the powerfist on the lord, it wastes his good initiative. Strength 9 powerfist is cool, but lightning claws would be better.
Bezerkers: IMO, powerfist is better, Extra Armor is a better buy on the rhino.
Plague marines are better orr with 2 plasma guns.
Possessed: Even numbers are better.
"SP" sorry, I'm not sure what that means.
5 flamers isn't as effective as it may look on paper.
It's alot of gear on the terminators, but not bad.
land raider would like Extra armor or Daemonic Possession.
Obliterator and Defiler are ok choices.
For the lord, his steed is a juggernaught of khorne... which you can scratch build or just get one from the classic section at the GW online site.
My 2 Cents.