HD silencers can cost quite a bit. To me it would make more sense just to buy a new more silent HD, if your HD indeed is loud. Quick way to test this is to unpulg your HD power cable while in BIOS.
I guess the most silent HDs atm are Samsung Spinpoint P80 and Maxtor DiamondMax 10. Most people here would probably recommend Seagate, but they just aren't as quiet as p80 and DM10, nor as fast as DM10. Some people wouldn't recommend Maxtors just because they have bad experiences with them before, but as you already own Maxtor I wouldn't see an issue here.
And about fans, I really suggest you read this http://forums.silentpcreview.com/viewtopic.php?t=16393
I wouldn't worry about the case duct. The reason why Antec has postponed the release of the case is probably because they made some changes to it, I'd suggest the ducting could change a bit.
Personally I wouldn't consider buying a new mobo, since you are currently running a agp graphics and s754 cpu and you most likely don't care about overclocking anyway since you bought a SFF in the first place. But if you decide you want a new mobo DFI LANPARTY UT nF3 250Gb Athlon 64 is the only real choise if you don't want to change you cpu and gpu at the same time. Upgrading from you system to a s939 system would be a waste of money at this point, since your comp is pretty good anyway. I wouldn't consider upgrading before AMD has socket M2 dual cores out.
I guess the most silent HDs atm are Samsung Spinpoint P80 and Maxtor DiamondMax 10. Most people here would probably recommend Seagate, but they just aren't as quiet as p80 and DM10, nor as fast as DM10. Some people wouldn't recommend Maxtors just because they have bad experiences with them before, but as you already own Maxtor I wouldn't see an issue here.
And about fans, I really suggest you read this http://forums.silentpcreview.com/viewtopic.php?t=16393
I wouldn't worry about the case duct. The reason why Antec has postponed the release of the case is probably because they made some changes to it, I'd suggest the ducting could change a bit.
Personally I wouldn't consider buying a new mobo, since you are currently running a agp graphics and s754 cpu and you most likely don't care about overclocking anyway since you bought a SFF in the first place. But if you decide you want a new mobo DFI LANPARTY UT nF3 250Gb Athlon 64 is the only real choise if you don't want to change you cpu and gpu at the same time. Upgrading from you system to a s939 system would be a waste of money at this point, since your comp is pretty good anyway. I wouldn't consider upgrading before AMD has socket M2 dual cores out.