Stuff a beast into a sonata?

I'm finally assembling the components for a pretty beefy beast and want to double-check if I'm being stupid/crazy in the case selection.

Da Beast:
- P4 3.0GHz
- Intel D875PBZ (875 chipset)
- 2x512 DDR400
- ATI 9800 PRO
- 2x WD Raptor
- 1x 250GB Western Digital "Caviar"
- odds & ends like a CD ROM, a DVD burner, a soundcard, a firewire card ...

Da Box :
Antec Sonata with 380W "True Power"

I'm worried about:
1) getting too hot
2) not having enough power

Am I worrying needlessly? Will it all just be OK? I don't plan to overclock or anything, but still ... that's a lot of hard drives spinning around really fast. Clearly, with a plan like this, sound is not my top priority.

all great exept hd once u hit that large a size u can really lose speed i would go with 2 smaller ones in my experiance up to 120gb hd are good

Ultimately, I found no good answers to these questions : how much juice do I need? How much airflow do I need? I understand why getting authoritative and correct answers to these would be really hard, but it does seem that there should be more explicit rules-of-thumb.

Anyway, I gave in to fear and got a big CoolerMaster case (an OEM version of the ATCS MRO-16 from the THG case review, with an airflow rating of "10" ) and an Antec 550W "True Power" supply. (Basically, a more powerful version of the same PSU from the Sonata.)

I ordered some adjsutable speed Zalman fans to replace the standard case fans. I figure I'll put it all together, see how bad the volume is, and then start fixing one thing at a time. (rubber grommets, case padding, etc.)

So, aside from the fact that the package (case+PSU) cost about 4x the Sonata case+PSU and I bought it only from irrational fear, I'm pretty psyched.