DL180 might be quieter... it is the baby server. DL380 is full heavy iron.
You can do either 2 P440s, 1 P840 or P440+expander ... what raid type are you wanting? If you want 1 single array... you need 440+expander or 840... if you are looking for ZFS or some software raid do a 1 or 2 240s or 1 h240+expander if you care less about latency.
For my performance boxes... I have P440ar + P840 and use the onboard for 2 drives off the back.
That gives me 24 drives in the front hotswap with no expanders and 2 in the back to boot from off the chipset.
You can do either 2 P440s, 1 P840 or P440+expander ... what raid type are you wanting? If you want 1 single array... you need 440+expander or 840... if you are looking for ZFS or some software raid do a 1 or 2 240s or 1 h240+expander if you care less about latency.
For my performance boxes... I have P440ar + P840 and use the onboard for 2 drives off the back.
That gives me 24 drives in the front hotswap with no expanders and 2 in the back to boot from off the chipset.